Fix renaming of the tags
We should enver delete/rename actual tags in the database, because these tag will be automatically recteated on the next Krita startup when it starts to sync them with the bundles/storages.
Instead, we should just inactivate the source tag and move all the resources into the destination tag.
The same approach is already used in the overriding technique of addTag(). I guess we just forgot to implement the same thing in renaming.