mod_pubsub_serverinfo: Consider sibling vhosts 'connected' Prosody does not have s2s connections between vhosts. Multiple domains will therefor not show up as each-other 'remote domains'. With this commit, the module considers vhosts permanently s2s-connected. Additional debug logging has been added.

This module blocks configured queries that change server state.

E.g. to make vCard storage read-only:

``` lua
readonly_stores = {
	vcard = { "vcard-temp", "vCard" };
}
```