mod_compat_roles: New module providing compat shim for trunk's new role API The new role API is translated to is_admin() calls on older versions. On newer versions (which have the role API) this module does nothing. It allows modules to drop their use of is_admin() (which is not available in trunk) and switch to the new role API, while remaining compatible with previous Prosody versions.

This module blocks configured queries that change server state.

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

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