This diff adds the 192kbps OPUS transcoding profile named
opus_audiophile. While 128kbps is already near transparent and good
for most use cases, sometimes (or by some people) a bit more is preferred.
These are typically for dedicated high quality wireless audio link
(A2DP-bluetooth) enabled headphones and Hi-Fi adapters.
The 160-192kbps range is considered to be transparent with very low
chance of artifacts (only with very few and specific samples)[1][2].
[1] https://wiki.hydrogenaud.io/index.php?title=Opus
[2] https://ceur-ws.org/Vol-2654/paper25.pdf
fixes#106
* Added support to TranscodedContentType and TranscodedSuffix
* Make sure that we have a profile
* Fix linting
* Fixed use of NewTCTrackByFolder instead of NewTrackByTags in handlers_by_tags.go
simplify a bit
