mod_http_oauth2: Focus username field automatically Reduces effort, not having to click or tab to focus the username field. Should have no negative effects since there's no other elements one might want to focus.

This module blocks configured queries that change server state.

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

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