Support ad-hoc commands

With different rights for the admin.

List of ideas tu support:

list the connected JIDs
On which server each JID is connected, the user nickname on that server and the list of chans they are in.
Disconnect any JID from the gateway
Ban any JID from accessing the gateway

(from redmine: created on 2014-05-05, closed on 2014-06-10)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information