Spec out API response for get modules endpoint

[f0ssel]

Example:

display_name: code-server
description: VS Code in the browser
icon: ../.icons/code.svg
maintainer_github: coder
verified: true
tags: [helper, ide, web]

// generated source code
type ModuleData struct {
	Name string
	CodeSnippet string
}

var APIResponses = []ModuleData{
	{
		Name: "hey",
		CodeSnippet: "my code",
	},
}


// normal source code
func (s Server) listModules() {
	api.Write(APIResponses)
}

Plus the code snippet data from #412

This should be a shared struct that will both be used when parsing readmes and will be served from the API.