audio/owntone: import version 28.4

OwnTone is an open source (audio) media server.

Owntone allows sharing and streaming your media library to iTunes
(DAAP1), Roku (RSP), AirPlay devices (multiroom), Chromecast and also
supports local playback.

You can control OwnTone via its web interface, Apple Remote (and
compatible DAAP/DACP clients), MPD clients or via its JSON API.

Besides serving your local music, podcast and audiobook media files,
OwnTone supports internet radios and Spotify (requires Spotify premium
account).

Prior to version 28, OwnTone was called forked-daapd, which again was
a rewrite of mt-daapd (Firefly Media Server).