Allows windows (or users via the rule system) to block compositing while they're present.
The user still can resume and re-suspend compositing at any time (but if it has originally been suspended for a blocking client it will be resumed the moment the last blocking client disappears)

Outstanding issue is that the rules to not allow to apply by fullscreen mode.
No real idea how we should handle this (add to rules globally or do some rule specific)

Rule based & "xprop -f _KDE_NET_WM_BLOCK_COMPOSITING 32a -set _KDE_NET_WM_BLOCK_COMPOSITING 1"
No client internal property setting tested (so far) but it should work as well... ;-)