dvr: New fmt spec for per-dir seasons and one movie per dir. (#4667)

dvr: New fmt spec for per-dir seasons and one movie per dir. (#4667)

Previously the $q format specifier would only output movies as:
	tvmovies/title (yyyy).ts

However, a common alternative is to store each movie in its
own sub-directory:
	tvmovies/title1 (yyyy)/title1 (yyyy).ts
	tvmovies/title2 (yyyy)/title2 (yyyy).ts

Similarly for episodes we output:
	tvshows/title/title - SxxEyy.ts

But a common alternative is to have one directory per season:
	tvshows/title/Season 1/title - S01Eyy.ts
	tvshows/title/Season 2/title - S02Eyy.ts

So we now add a "$3q" to output these common alternatives, as requested
in the forums.

Also add equivalent "$3Q" to output without the "genre" prefix
i.e., without "tvshows/" or "tvmovies/".

Issue: #4667