main/postmarketos-base-ui: add audio subpackages
This MR implements audio-pipewire
and audio-pulseaudio
subpackages for postmarketos-base-ui
. This is required for the implementation for the proposal here: #2718.
To summarize the proposal: the goal is to make it where audio stacks are not hard-coded to UI packages. By making UI packages rely on postmarketos-base-ui-audio
it will be easier to switch out audio stacks depending on user or UI choice.