mod_http_oauth2: Declare additional client registration fields as strings Previously any property not listed in the schema was allowed in any form, which is probably a bit too liberal. Instead, limit extra fields to simple strings, which should still allow localized versions of the various URIs and descriptive properties per RFC 7591 §2.2

# mod_tos

A very drafty module to implement some kind of Terms of Service acceptance
tool.

Currently, this only works with clients implementing this very drafty
protocol. The result of the experiments will be an update to the
[ToS ProtoXEP](https://xmpp.org/extensions/inbox/tos.html), with the goal
of acceptance.