Update the model deletion confirmation page in the admin UI.
Review Request #1904 — Created April 16, 2020 and updated
This adds a custom template for the delete confirmation page used in the admin UI for models. Django's default template doesn't render quite well, and doesn't offer any flexibility for customization. Our version is a bit friendlier and fits our modern style in the admin UI. This covers the main confirmation page, the "protected objects" confirmation page (used if a `ForeignKey` is set to prevent deletion of the referenced object using the `PROTECT` flag), or if the user doesn't have permission for one or more objects. Testing Done: Tested the standard deletion page, the permission errors page, and the protected relations page. Tested all the buttons on all pages. Reviewed at https://reviews.reviewboard.org/r/10975/
nee noch nicht erledigt