title: drupal 8 create an page in admin section in admin/structure/customformdatalisting
body: <p>I am trying to create a custom admin page in drupal 8 admin
  i have create a custom module name custom_admin also I have added the below code in </p>
  
  <pre><code>"custom_admin.routing.xml"
  custom_admin.contactformlisting:
    path: '/admin/structure/contactformlisting'
    defaults:
      _content: 
  '\Drupal\custom_admin\Controller\AdminController::contactformlisting'
      _title: 'Contact Form Listing'
  requirements:
      _permission: 'administer contact forms listing'  
     _access: 'TRUE'
  </code></pre>
  
  <h2>custom_admin_permissions.yml</h2>
  
  <pre><code>administer contact forms listing:
    title: 'Administer contact forms listing'
  </code></pre>
  
  <p>in custom_admin.links,menu.yml</p>
  
  <pre><code>custom_admin.contactformlisting:
    title: Contact Form Data Listing 
    description: 'This is a contact form listing page link`enter code here`'
    parent: system.admin_structure
    route_name: custom_admin.contactformlisting
  </code></pre>
  
  <p>But still revceving Page not Found can anybody help me in these</p>