Ask if user really wants to remove him/her/themselves as owner of folder (or resource)

[pbek]

Follow up on #503 (comment)...
I'm not sure if this should be considered a bug or feature request...

It would be great if the user would be asked if he/she/they really want(s) to remove him/themselves as owner of a folder (or resource).

What you did

• Have a folder with resources, shared with at least one other person as owner
• Share resource with other users and by accident manage to remove yourself as owner
• Press Save

What happened

• Folder is not owned by you anymore, you cannot share or edit it anymore

What you expected to happen

• When clicking Save I get a warning that I remove myself as owner, I need to click something to allow that