mod_muc_http_auth: Allow for enabling/disabling per user host IMPORTANT: This is a breaking change. The `muc_http_auth_enabled_for` and `muc_http_auth_disabled_for` options are now maps (with user hosts as keys) and not sets.

This module blocks configured queries that change server state.

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

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