yggtorrent: search by category

[ilike2burnthing]

Removes old category setting and the new sub-cat setting from #14248 earlier.

Closest thing to addressing Prowlarr/Indexers#55 other than performing a separate search for every selected sub-category.

See info note:

To avoid unnecessary additional requests, it's recommended to only use indexer-specific categories (>=100000) when configuring this indexer in Sonarr, Radarr, and Lidarr, or when manually searching in TV, Movies, and Audio categories.