Propose to delete data from deactivated persistent features

In #12109 (closed) we are working on a documentation patch to explain people how to delete the files corresponding to deactivated persistent features. Still, we shouldn’t rely on having people ready the doc so much…

Instead what about asking people whether they want to delete the corresponding data when we detect that some features have been deactivated?

If we agree on this, I could draft a UI.

Related issues

• Related to #12109 (closed)
• Is duplicate of #8447

Original created by @sajolida on 12448 (Redmine)