mpv: use some Noto Sans subfamilies as fallback

The Droid Sans Fallback font had some problems, most notably misplaced
umlaut diareses. The bundled Noto Sans families fix this problem and
also cover more glyphs.

In addition, the fontconfig configuration has been changed to prefer
them as sans-serif fonts to avoid OSD/OSC problems.
mpv: disable openal-soft for now

It’s not a recommended AO, and git master has been failing for a
while now. I’ll consider re-enabling and fixing it if someone
complains.