webui: changed rights for playlist, dvrfile, fixes #2409

- /dvrfile requires (advanced) streaming or recorder rights
- /play requires (advanced) streaming or recorder rights
- /playlist requires rights depending on functionality
  - dvr playlists requires recording rights
  - channel and tags playlist requires streaming rights
muxer libav: review again the h264 filter payload free code
service mapper: fix the abort due to missing streaming target initialization
webui: the /play redirector - add more user-agent direct streaming, fixes #2412

- 'VLC/'
- 'MPlayer '
- 'Lavf/' (ffmpeg, libav)
- shoutcastsource (some media players?)