Add configuration entity for multiple redirects

lostcarpark → changed the visibility of the branch 3513851-add-config-entity to hidden.

I have added a "verify email" config entity.

I was hoping to use PHP attributes to define the entity. However, this is only supported from Drupal 11.1. As I need to support D10, at least for the time being, I have converted the attributes back to a comment annotation.

The config form allows adding, editing, and deleting of entities.

The fields of the entity are as listed above.

I have written a test to add, edit, and delete a "verify email" entity, and it is passing for all versions GitLab CI tests against.

I think this is ready to merge.

!2 merged.

Automatically closed - issue fixed for 2 weeks with no activity.