Add Kconfig file for the media proxy, for high-level media control
configuration.
The media proxy did not have a Kconfig file, it was relying on the
Kconfigs for GATT media control client and server.
The purpose is to unify the media control configurations, to make the
different media control functionalities available separately, and to
separate the high-level media control from the bluetooth media control
server and client.
Signed-off-by: Asbjørn Sæbø <asbjorn.sabo@nordicsemi.no>
29aa654600