[Standards] MUC History clearing

[Lirette, Keith J. CONTR J9C618]

I would like to suggest an addition to XEP-0045 to allow for clearing of
history in a MUC room.

There are numerous use cases where this would be useful: after changing
the room topic, prior to starting a new discussion in an existing room,
prior to adding new members to a room, ....

I suggest adding the functionality to the muc#owner schema.

SEND: <iq  xmlns="jabber:client" id="clearHistory_xTu97"
from="user1 at server to="mtgroom_1 at conference.server" type="set"><query
xmlns="http://jabber.org/protocol/muc#owner"><clear_history/></query></i
q>

RECV: <iq  xmlns="jabber:client" id="clearHistory_xTu97"
to="user1 at server" type="result"/>


A notification to users would be sent in the same fashion as room
configuration changes.


RECV: <message from='darkcave at macbeth.shakespeare.lit' to='user2 at server'
type='groupchat'>
		<x xmlns='http://jabber.org/protocol/muc#user'>
			<status code='175'/>
		</x>
      </message>


Keith J. Lirette