[KCM] Add speaker placement test
An equivalent to the Phonon KCM speaker test.
One step closer to T9091
When siwtching profiles the appropriate setup is shown.
Sound is working for Stereo, 5.1/7.1 is not tested because I don't have the hardware for it.
Input-only profile still shows Front-left and front-right
Reviewed By: drosca
Subscribers: ngraham, VDG, plasma-devel
Differential Revision: https://phabricator.kde.org/D13931