Currently this will just grant full access to all clients.
A future version will refine that to grant access to specific
objects only.

This provides high level volume controls for the AGL audiomixer
binding and the applications using it.

This is a cleaner way to interface with the remote pipewire daemon.
The WpRemote base class can be subclassed also for interfacing
with other daemons (hardware-specific managers, etc)

This allows loading of config and modules when deployed in
the target system without setting environment variables.

After discussing things at the AGL May 2019 F2F meeting
and reflecting on the initial design of WirePlumber,
it became clear that it needed a fresh start.