Add Granular Permissions

[aweingarten]

Business Requirements

• As a site-builder I want granular permissions for controlling access to vital functionality

Technical Requirements

• Add a permission for accessing the global cache-clear tab
  /admin/config/development/cloudflare/cache-clear
• Add a permission for accessing the zone settings tab
  /admin/config/development/cloudflare/zone
• Make sure that the API creds tab is protected by standard admin permissions
  /admin/config/development/cloudflare
• Add automated tests to validate that ^^ works.