Use libfeedback instead of GTK's media API

This allows to use haptic and (if wanted) LED based feedback on top of audio and adhere to the systems quietness settings.

It also allows users to adjust the sound played via the sound theme. Alarms can override the system wide quietness setting so they're not missed. On desktop systems where usually no haptic is available only the sound profile is used but feedbackd can also e.g. leverage the status LED on Framework or Purism laptops.

Feedbackd is maintained on fdo and used in projects like phosh, gnome-calls and others since about half a decade.