* fix mapping of return values for get_or_register_3pid_guest

Make generating SQL bounds for pagination generic

* expose SlavedProfileStore to ClientReaderSlavedStore

* Stop telling people to install the optional dependencies.

They're optional.

Also update the postgres docs a bit for clarity(?)

Add an option to disable per-room profiles

Re-order registration stages to do msisdn & email auth last

Merge pull request #5187 from matrix-org/dbkr/only_check_threepid_not_in_use_if_actually_registering

Only check 3pids not in use when registering

This will allow us to reuse the same structure when we paginate e.g.
relations

Allow client event serialization to be async

Expose DataStore._get_events as get_events_as_list

Use correct config option for ratelimiting in tests

Co-Authored-By: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

Co-Authored-By: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

We checked that 3pids were not already in use before we checked if
we were going to return the account previously registered in the
same UI auth session, in which case the 3pids will definitely
be in use.

https://github.com/vector-im/riot-web/issues/9586

This is in preparation for reaction work which requires it.