1135: Fixed issues with incorrect generation of resolver class

[makzef]

Description (*)

What were done:

1. Added new inspection that shows warning about incorrect resolver class format (FQN).
2. Fixed inspection that shows error message resolver class not exists for description values (in schema.graphqls file), but should only apply checks for class values.
3. Added error message when user trying to create resolver that consists less than 3 parts of FQN. The class format should look like this: {VENDOR}\{MODULE}\{DIRECTORY OR DIRECTORIES OR NOTHING}\{CLASSFILE}, so only one part is optional - directory(-ies), that's why FQN should have minimum 3 parts.
4. Fixed an issue when resolver file generated by incorrect path (related to directory creation described in scheme above), including incorrect file generation in the module root.
5. Some code improvements related to above resolved issues.

graphql_resolver_class.mov

Fixed Issues (if relevant)

1. Fixes [Bug] IndexOutOfBoundsException: CreateResolverClassQuickFix.applyFix(CreateResolverClassQuickFix.java:43) #1135

Questions or comments

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with integration/functional tests (if applicable)
• All automated tests passed successfully (all builds are green)

[bohdan-harniuk]

Hello, @makzef!
Great work!
Thank you!