dvr: Allow selecting (xmltv) category in autorec. (#4665)

dvr: Allow selecting (xmltv) category in autorec. (#4665)

The xmltv import supports categories such as "movie",
"animated", "biography", so allow autorec to record via these
categories.

We do this by providing three drop-down selectors in the
advanced settings of the autorec. This allows the user
to easily discover the categories available whilst
providing enough capability for reasonably advanced
recordings when coupled with the existing fulltext search.

Issue: #4665