mod_http_oauth2: Allow 'login_hint' as a substitute for OIDC 'select_account' prompt If the OIDC 'prompt' parameter does not contain the 'select_account' then it wants us to skip account selection, which means we have to figure which account to authenticate somehow. One way could be have this stored in a cookie from a previous successful login. Another way would be to have the account passed as a hint, which is what we add here.

This module helps make BOSH and WebSocket connection endpoints
discoverable via the HTTP method described in
[XEP-0156](https://xmpp.org/extensions/xep-0156.html#http).