Add routes to allow git actions on snippet repositories

What does this MR do?

In this MR we implement the following:

• Refactors the git_http routes because, for now, snippet repositories won't support LFS (mainly because lfs_enabled is a project feature and we have to think if we could enable it by default for personal snippets).
• It also updates the GitHttpController(s) and the SSH internal API to allow basic cloning/pushing/pulling operations for resources other than projects.

Refs #39176 (closed) Closes #205666 (closed)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Separation of EE specific content

app/controllers/repositories/git_http_controller.rb

@@ -87,7 +87,7 @@ def access
       @access ||= access_klass.new(access_actor, container, 'http',
         authentication_abilities: authentication_abilities,
         namespace_path: params[:namespace_id],
-        project_path: project_path,
+        repository_path: repository_path,
         redirected_path: redirected_path,
         auth_result_type: auth_result_type)
     end
@@ -109,8 +109,8 @@ def access_klass
       @access_klass ||= repo_type.access_checker_class
     end
 
-    def project_path
-      @project_path ||= params[:repository_id].sub(/\.git$/, '')
+    def repository_path
+      @repository_path ||= params[:repository_id].sub(/\.git$/, '')
     end
 
     def log_user_activity