Resolve "Add Release API Endpoints for Groups"

What does this MR do and why?

This merge request adds an API endpoint at /api/v4/groups/:id/releases that will provide all the releases in any projects that belong to a group. Currently supports order_by, sort and simple params

Screenshots or screen recordings

Truncated example output from endpoint

	{
		"name": "duptag",
		"tag_name": "testtag",
		"description": "",
		"created_at": "2022-01-10T15:23:15.529Z",
		"released_at": "2022-01-10T15:23:15.529Z",
		"author": {
			"id": 1,
			"username": "root",
			"name": "Administrator",
			"state": "active",
...

How to set up and validate locally

1. Fetch releases for a group at http://gdk.test:3000/api/v4/groups/:id/releases where :id is the id of a group with subprojects with releases

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #345534 (closed)