DEVDOCS-6313: [update] currencies endpoints (#858)

<!-- Ticket number or summary of work -->
# [DEVDOCS-6313]


## What changed?
Updated the currencies endpoints
- removed `date_created` and `date_modified`, replaced with
`last_updated`.
- created new schemas for PUT and POST endpoints.
- added `default_for_country_codes` and `use_default_name`
- removed required for the currency_code field for the PUT request body
- updated the PUT request body
- updated the POST request body
- added readonly for the last_updated field

## Release notes draft
<!-- Provide an entry for the release notes using simple, conversational
language. Don't be too technical. Explain how the change will benefit
the merchant and link to the feature.

Examples:
* The newly-released [X feature] is now available to use. Now, you’ll be
able to [perform Y action].
* We're happy to announce [X feature], which can help you [perform Y
action].
* [X feature] helps you to create [Y response] using the [Z query
parameter]. Now, you can deliver [ex, localized shopping experiences for
your customers].
* Fixed a bug in the [X endpoint]. Now the [Y field] will appear when
you click [Z option]. -->
* 

## Anything else?
<!-- Add related PRs, salient notes, additional ticket numbers, etc. -->

ping {names}


[DEVDOCS-6313]:
https://bigcommercecloud.atlassian.net/browse/DEVDOCS-6313?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

Author: bc-traciporter

reference/currencies.v2.yml

@@ -80,7 +80,6 @@ paths:
         Creates *Currency*.
 
         **Required Fields** 
-
         * name
         * currency_code
         * currency_exchange_rate
@@ -92,8 +91,7 @@ paths:
 
         **Read-Only Fields**
         * id
-        * date_created
-        * date_modified
+        * last_updated
 
 
         The `is_default` property can only be set to true. The value of `is_default` cannot be unset, only overridden. To change the storeʼs default currency in the BigCommerce control panel, please see [Managing Currencies (Help Center)](https://support.bigcommerce.com/s/article/Managing-Currencies-Beta).
@@ -154,8 +152,7 @@ paths:
         **Read-Only Fields**
 
         * id
-        * date_created
-        * date_modified
+        * last_updated
         * currency_code
 
 
@@ -198,10 +195,8 @@ paths:
 components:
   schemas:
     currency_Post:
-      $ref: '#/components/schemas/currency_Base'
-    currency_Base:
-      title: currency_Base
-      required:
+     title: currency_Post
+     required:
         - currency_code
         - currency_exchange_rate
         - decimal_places
@@ -210,6 +205,159 @@ components:
         - thousands_token
         - token
         - token_location
+     type: object
+     properties:
+        is_default:
+          type: boolean
+          description: Specifies the store’s default currency display format. For
+            write operations, only true value is accepted. When set to true, it cannot
+            be unset, only overridden.
+          example: false
+        country_iso2:
+          type: string
+          description: 2-letter ISO Alpha-2 code for this currency’s country.
+          example: EU
+        currency_code:
+          type: string
+          description: 3-letter ISO 4217 code for this currency.
+          example: EUR
+        currency_exchange_rate:
+          type: string
+          description: Amount of this currency that is equivalent to one U.S. dollar.(Float,
+            Float as String, Integer)
+          example: "0.849"
+        auto_update:
+          type: boolean
+          description: Specifies whether to use the Open Exchange Rates service to
+            update the currency conversion. A value of false specifies a static conversion
+            value. auto_update only applies to non-transactional currencies.
+          example: true
+        token_location:
+          type: string
+          description: Specifies whether this currency’s symbol appears to the “left”
+            or “right” of the numeric amount.
+          example: left
+        token:
+          type: string
+          description: Symbol for this currency.
+          example: €
+        decimal_token:
+          type: string
+          description: Symbol used as the decimal separator in this currency.
+          example: "."
+        thousands_token:
+          type: string
+          description: Symbol used as the thousands separator in this currency.
+          example: ','
+        decimal_places:
+          type: integer
+          description: Number of decimal places to show for this currency.
+          example: 2
+        name:
+          type: string
+          description: Name of the currency.
+          example: Euro
+        enabled:
+          type: boolean
+          description: If the currency is active on the store.
+          example: false
+        is_transactional:
+          type: boolean
+          description: Indicates if the currency is set as transactional or not. False
+            means display only currency
+          example: false
+     description: Currency Object
+     example:
+        is_default: false
+        country_iso2: EU
+        currency_code: EUR
+        currency_exchange_rate: '0.849'
+        auto_update: true
+        token_location: left
+        token: €
+        decimal_token: "."
+        thousands_token: ','
+        decimal_places: 2
+        name: Euro
+        enabled: false
+    currency_Put:
+     title: currency_Put
+     required:
+        - currency_exchange_rate
+        - decimal_places
+        - decimal_token
+        - name
+        - thousands_token
+        - token
+        - token_location
+     type: object
+     properties:
+        is_default:
+          type: boolean
+          description: Specifies the store’s default currency display format. For
+            write operations, only true value is accepted. When set to true, it cannot
+            be unset, only overridden.
+          example: false
+        country_iso2:
+          type: string
+          description: 2-letter ISO Alpha-2 code for this currency’s country.
+          example: EU
+        currency_exchange_rate:
+          type: string
+          description: Amount of this currency that is equivalent to one U.S. dollar.(Float,
+            Float as String, Integer)
+          example: "0.849"
+        auto_update:
+          type: boolean
+          description: Specifies whether to use the Open Exchange Rates service to
+            update the currency conversion. A value of false specifies a static conversion
+            value. auto_update only applies to non-transactional currencies.
+          example: true
+        token_location:
+          type: string
+          description: Specifies whether this currency’s symbol appears to the “left”
+            or “right” of the numeric amount.
+          example: left
+        token:
+          type: string
+          description: Symbol for this currency.
+          example: €
+        decimal_token:
+          type: string
+          description: Symbol used as the decimal separator in this currency.
+          example: "."
+        thousands_token:
+          type: string
+          description: Symbol used as the thousands separator in this currency.
+          example: ','
+        decimal_places:
+          type: integer
+          description: Number of decimal places to show for this currency.
+          example: 2
+        name:
+          type: string
+          description: Name of the currency.
+          example: Euro
+        enabled:
+          type: boolean
+          description: If the currency is active on the store.
+          example: false
+        is_transactional:
+          type: boolean
+          description: Indicates if the currency is set as transactional or not. False
+            means display only currency
+          example: false
+     description: Currency Object
+     example:
+        currency_exchange_rate: "0.849"
+        token_location: left
+        token: €
+        decimal_token: "."
+        thousands_token: ','
+        decimal_places: 2
+        name: Euro
+    currency_Base:
+      title: currency_Base
       type: object
       properties:
         is_default:
@@ -222,6 +370,12 @@ components:
           type: string
           description: 2-letter ISO Alpha-2 code for this currency’s country.
           example: EU
+        default_for_country_codes:
+          type: array
+          items:
+            type: string
+          description: Default 3-letter ISO 4217 code for this currency.
+          example: [EU]
         currency_code:
           type: string
           description: 3-letter ISO 4217 code for this currency.
@@ -270,6 +424,10 @@ components:
           type: boolean
           description: Indicates if the currency is set as transactional or not. False
             means display only currency
+          example: true
+        use_default_name:
+          type: boolean
+          description: Default currency name
           example: false
       description: Currency Object
       example:
@@ -306,8 +464,6 @@ components:
             last_updated: 2018-06-12T14:41:56.000Z
             enabled: false
       x-internal: false
-    currency_Put:
-      $ref: '#/components/schemas/currency_Post'
     currency_Full:
       title: currency_Full
       allOf:
@@ -323,6 +479,7 @@ components:
             type: string
             description: Date the currency was last updated, created or modified.
             format: date-time
+            readOnly: true
       x-internal: false
   responses:
     currencyCollection_Resp: