backup info added to wiki

[Craig Ringer]

Hi folks

I've added some information about backing up a Cyrus server to the wiki. 
  I'm no expert so I'd love it if a few people could have a look at what 
I've written and make sure it all looks right. Much of the information 
was drawn from things discussed on the mailing list.

Any additions/clarifications would be much appreciated also.

The entry was made at
http://asg.web.cmu.edu/twiki/bin/view/Cyrus/Backup
and linked from:
http://asg.web.cmu.edu/twiki/bin/view/Cyrus/CyrusAdministration

I've also added a FAQ entry that's somewhat related, commenting on the 
non-working 'reconstruct -m' command:

Why does reconstruct -m not work? (ReconstructMailboxes)
[ http://asg.web.cmu.edu/twiki/bin/view/Cyrus/ReconstructMailboxes ]

I'm sure both of these could use some cleaning up - I just wanted to get 
them done and get some info on backups into the wiki. I'll try to come 
back to the entries later to clarify and reword where needed.

Craig Ringer