PulseAudio: Ability to mute everything except "allowed programs"

[SF007]

Binary package hint: padevchooser

In PulseAudio, it would be nice to have an option to mute all programs except the ones allowed to produce sound, for example:
Mute everything except the media player, because sometimes there are some crazy flash ads with sound... (very annoying!)
And disabling every potential "annoyer" is hard:
-sounds can come from many browsers
-each browser can have many plugins
-even non-browser programs can have annoying sounds
-and even if we disable all that, once the program is closed those settings disappear! (Bug #217516)

I think many users would find this a very useful thing.