mod_http_oauth2: Allow only l10n variants of name in client metadata Since "client_name" seems to be the only human readable non-URI property that makes sense to have localized version of. Therefore it seems excessive to allow arbitrary additionalProperties. We don't make use of localized versions of client_name and URIs yet, but it would be nice to do so.

This module blocks configured queries that change server state.

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

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