Draft: Separate speaker/earpiece for voice calls and declare HW controls

Currently, the speaker and earpiece are used as a single stereo device in the VoiceCall profile. However, voice calls are mono and usually routed to either the earpiece or the speaker. It therefore makes sense to expose both as separate devices to clients, so we can select the appropriate output device.

Additionally, volume/muting can be changed using hardware controls for all input/output devices in this profile, but such controls weren't defined in the UCM config. This was leading PulseAudio/PipeWire to only change the volume in software, which had no effect during voice calls as audio streams are fully routed in hardware in this case. This MR also includes HW controls definitions for the voice call profile, except for the headset mic (no headset with working mic available for testing).