Phonon KDED module: Improve finding virtual devices from ALSA

PhononServer was not finding any usable capture devices. It
was skipping almost all useful devices. Commented out the
block for skipping those.

Prevent devices with empty names when their description
is empty. This should not happen, but it's just in case.

Eliminate any front, center, rear, surround virtual devices from
capture device candidates.

Additionally, there will be only one device with an unique id, with
one or more access descriptors.

Replace default: with hw: for capture devices, to enable capture
working with Phonon-VLC.