Description of the need

We should add something to the status report about CKEditor 4 being deprecated and how to upgrade to CKEditor 5.

Proposed solution

To be discussed, but maybe a REQUIREMENT_WARNING output by ckeditor_requirements(), if the module is enabled it just always outputs a warning that the module is deprecated?

Alternatives that have been considered

TBD

GitHub Link: 
https://github.com/backdrop/backdrop-issues/issues/6346
GitHub Issue #: 
6346