Remove Ci::ApplicationController

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

CHANGELOG

@@ -82,6 +82,7 @@ v 8.13.0 (unreleased)
   - Retouch environments list and deployments list
   - Add Container Registry on/off status to Admin Area !6638 (the-undefined)
   - Grouped pipeline dropdown is a scrollable container
+  - Cleanup Ci::ApplicationController. !6757 (Takuya Noguchi)
   - Fix a typo in doc/api/labels.md
 
 v 8.12.5 (unreleased)

app/controllers/ci/application_controller.rb

-module Ci
-  class ApplicationController < ::ApplicationController
-    def self.railtie_helpers_paths
-      "app/helpers/ci"
-    end
-  end
-end

app/controllers/ci/lints_controller.rb

 module Ci
-  class LintsController < ApplicationController
+  class LintsController < ::ApplicationController
     before_action :authenticate_user!
 
     def show

app/controllers/ci/projects_controller.rb

 module Ci
-  class ProjectsController < Ci::ApplicationController
+  class ProjectsController < ::ApplicationController
     before_action :project
     before_action :no_cache, only: [:badge]
     before_action :authorize_read_project!, except: [:badge, :index]