Require our own custom cops; Remove missing cops

Also try to use the same config from EE

.rubocop.yml

@@ -3,6 +3,7 @@ inherit_gem:
     - rubocop-default.yml
 
 inherit_from: .rubocop_todo.yml
+require: ./rubocop/rubocop
 
 AllCops:
   TargetRailsVersion: 4.2

rubocop/rubocop.rb

-require_relative 'cop/active_record_dependent'
 require_relative 'cop/gitlab/module_with_instance_variables'
 require_relative 'cop/include_sidekiq_worker'
 require_relative 'cop/migration/add_column'
@@ -18,6 +17,4 @@ require_relative 'cop/migration/update_column_in_batches'
 require_relative 'cop/migration/update_large_table'
 require_relative 'cop/project_path_helper'
 require_relative 'cop/rspec/env_assignment'
-require_relative 'cop/rspec/single_line_hook'
-require_relative 'cop/rspec/verbose_include_metadata'
 require_relative 'cop/sidekiq_options_queue'