RFC - Removing System Bell KCM

[David Edmundson]

What does it do:
 - calls XChangeKeyboardControl to set the length/pitch or the beep on
the internal beep of old PCs.

Who calls uses this bell:
 - the KCM to configure the bell.. and that's it from within KDE

No one other KDE app explicitly loads kcmbellrc or calls XBell.
So we have a KCM for configuring something we don't use from KDE.
One can still echo -e "\aBeep!" from a konsole, but then they can
configure it there too.

I don't think it's something relevant anymore, and I'm not entirely
convinced this code even works.

David