mod_http_oauth2: Reuse JWT issuance time as substitute for auth time Makes the token shorter. Since iat and auth_time are generated at about the same time they would only differ by a few microseconds anyway.

This module blocks configured queries that change server state.

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

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