Create custom permissions per verification form

Problem/Motivation

Currently, the verification form is always available, meaning anonymous users will always be able to create users with it. This may not always be desirable, so it would be good to make it permission based.

Additionally, logged in users always skip the verification form at present. Allowing this to be controlled by permissions would make the module more flexible.

Steps to reproduce

Create a verification form and log out. Navigate to the form and verify it is available. Next, log in and navigate to the verification, and observe the user is redirected to the form's destination.

Proposed resolution

Create two permissions "Access verification form _______" and "Skip verification form ______". A follow on task will limit access using them.

Remaining tasks

1. Add a new class to the /src called VerifyEmailPermissions.
2. Use the Drupal\Core\DependencyInjection\AutowireTrait in the class (I think this should work - if I'm wrong, a create function will be needed instead).
3. Add a constructor to that takes a parameter of type Drupal\Core\Entity\EntityTypeManagerInterface and promotes to a property.
4. Add a public method of the class called "permissions" that should do the following tasks:
   • Initialize permissions as an empty array.
   • Load the storage for verify_email.
   • Query the verify email entities, and for each one add two elements to the permission array, one with a key of "access verify $id" and a translatable value of "Access verification form $tag", and the second with a key of "skip verify $id" and a translatable value of "Skip verification form $tag".
   • Return the array of permissions.
5. Add an entry to verify_email.services.yml, defined as the fully qualified class name. Autowiring will take care of the properties, but the definition will need the following tag:
   

     tags:
       - { name: 'user.permission_provider', method: 'createPermissions', provider: 'verify_email' }
   

   
   Add a permission_callbacks entry to verify_email.permissions.yml, specifying the path to the fully qualified class name and the permission function
6. In the setup of test VerifyEmailSetupTest, add "administer permissions" to the permissions of the created user.
7. In testVerifyEmailConfig, add a check after the form creation that loads the /admin/people/permissions page, and checks for the presence of "Access verification form Test verify email" and "Skip verification form Test verify email".

User interface changes

Only the new permissions on the permissions page.

API changes

None.

Data model changes

None.