metadata: return both movie and TV results when in non-automatic mode

This allows not having to fiddle with season or episode #. TV or movie entries are presented first depending on the guessed type.
We only do so if multiple results were already found
metadata: also look for artwork when scanning a single recording

no point waiting a day or having to run a full artwork scan
frontend: add search abilities to “change recording metadata” screen.

This will allow to search for inetref and set season/episode as well as subtitle and description.
Themes will have to be updated to enjoy this functionality by adding a “query_button” button.