Tighten LHDC v5 config validation and keep the codec encoder-only: do not add unsupported decode, delay query, or PipeWire-side ABR behavior.
Advertise the LHDC v5 sample rates and S16/S24 formats supported by liblhdcv5, parse the P7 bitrate range from peer capabilities, and initialize liblhdcv5 with the selected min/max bitrate indices. Keep fixed quality choices limited to the currently negotiable local max.
A2DP v1.4 uses the rfa bits for adding 5.1 and 7.1 configurations.
Clear those bits properly when sending configuration, in case remote
device sets them.
Make easier to package A2DP codecs separately, by splitting each to a
separate SPA plugin. Adjust the code to not use a global variable for
the codec list.
The A2DP SPA interface API is in the bluez5 private headers, and not
exposed in installed SPA headers, as it's too close to the
implementation.
