mod_vcard_muc: Add an alternative method of signaling avatar change When the avatar has been changed, a signal is sent that the room configuration has changed. Clients then do a disco#info query to find the SHA-1 of the new avatar. They can then fetch it as before, or not if they have it cached already. This is meant to be less disruptive than signaling via presence, which caused problems for some clients. If clients transition to the new method, the old one can eventually be removed. The namespace is made up while waiting for standardization. Otherwise it is very close to what's described in https://xmpp.org/extensions/inbox/muc-avatars.html

---
summary: 'Block outgoing stanzas from users'
...

Introduction
============

This module blocks all outgoing stanzas from a list of users.

Using
=====

Add mod_block_outgoing to the enabled modules in your config file:
``` {.lua}
modules_enabled = {
	-- ...
		"block_outgoing",
	-- ...
}
```

Either in a section for a certain host or the global section define which users and what stanzas to block:
``` {.lua}
block_outgoing_users = { "romeo@example.com", "juliet@example.com" }
block_outgoing_stanzas = { "message", "iq", "presence" }
```

block_outgoing_stanzas defaults to "message" if not specified.