Merge branch 're-organise-admin-two-factor-concerns' into 'master'

Make two factor concern module more auto-load friendly

See merge request gitlab-org/gitlab!43077

app/controllers/admin/sessions_controller.rb

 # frozen_string_literal: true
 
 class Admin::SessionsController < ApplicationController
-  include Authenticates2FAForAdminMode
+  include AuthenticatesWithTwoFactorForAdminMode
   include InternalRedirect
   include RendersLdapServers
 

app/controllers/admin/concerns/authenticates_2fa_for_admin_mode.rb → app/controllers/concerns/authenticates_with_two_factor_for_admin_mode.rb

 # frozen_string_literal: true
 
-module Authenticates2FAForAdminMode
+module AuthenticatesWithTwoFactorForAdminMode
   extend ActiveSupport::Concern
 
   included do

app/controllers/omniauth_callbacks_controller.rb

 # frozen_string_literal: true
 
 class OmniauthCallbacksController < Devise::OmniauthCallbacksController
-  include AuthenticatesWithTwoFactor
-  include Authenticates2FAForAdminMode
+  include AuthenticatesWithTwoFactorForAdminMode
   include Devise::Controllers::Rememberable
   include AuthHelper
   include InitializesCurrentUserMode