Headset profile saving does not work properly currently (only called on
metadata change; if headset-profile == current-profile, it doesn't get
saved etc.)
Change it to follow the logic:
- Each device has a "normal" and "switched" mode. The latter becomes
active if a "communication" input stream exists and the current
default sink is bluez sink. The switched mode is exited only when
there are no "communication" input streams.
- On transition normal->switched, record current profile as the "saved"
profile. Then switch to "headset" profile. If no headset profile
was saved previously, pick profile with input direction & highest
priority.
- On transition switched->normal, save currently active profile as the
"headset" profile. Then switch back to "saved" profile.
Monitor streams can be identified based on the stream.monitor property.
They should not be identified based on application name, because that
may be localized, and the previous code does not work properly on
non-English locale.
The "saved headset profile" is taken as the profile that was active when
the headset mode deactivates. So in case the user switches profile during
the time when the Communication input stream is active, the selected
profile is remembered next time.
