Add route for environments cross-project dashboard

ee/app/controllers/operations_controller.rb

@@ -10,6 +10,10 @@ class OperationsController < ApplicationController
   def index
   end
 
+  def environments
+    render :index
+  end
+
   def list
     Gitlab::PollingInterval.set_header(response, interval: POLLING_INTERVAL)
     projects = load_projects(current_user)

ee/config/routes/operations.rb

 # frozen_string_literal: true
 
 get 'operations' => 'operations#index'
+get 'operations/environments' => 'operations#environments'
 get 'operations/list' => 'operations#list'
 post 'operations' => 'operations#create', as: :add_operations_project
 delete 'operations' => 'operations#destroy', as: :remove_operations_project