Also set the release sha and author

Adds `# frozen_string_literal: true` to spec/models ruby files

Releases::Source and Releases::Link are covered by tests

Add spec for all release API - GET, POST, PUT, DELETE.
Also, fixes some minior bugs.

CreateReleaseService and UpdateReleaseService now takes all the release
attributes as constructor parameters. This will simplify attribute
expansion

This commit introduces Releases API under /api/v4/projects/:id/releases

* We are introducing release policies at project level.
* We are deprecating releases changes from tags, both api and web
interface.
* Tags::CreateService no longer create a release

This feature is controlled by :releases_page feature flag

This commit adds a name to each release, defaulting it to tag name,
keeps track of the SHA when a new release is created and tracks the
current user as release author.

Signed-off-by: Rémy Coutable <remy@rymai.me>

This reverts commit 3e991230.

# Conflicts:
#	app/models/project.rb

In 8278b763 the default behaviour of annotation
has changes, which was causing a lot of noise in diffs. We decided in #17382
that it is better to get rid of the whole annotate gem, and instead let people
look at schema.rb for the columns in a table.

Fixes: #17382

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>