Follow-up to https://github.com/matrix-org/synapse/pull/12083

Since we are now using the new `state_event_ids` parameter to do all of the heavy lifting.
We can remove any spots where we plumbed `auth_event_ids` just for MSC2716 things in
https://github.com/matrix-org/synapse/pull/9247/files.

Removing `auth_event_ids` from following functions:

 - `create_and_send_nonmember_event`
 - `_local_membership_update`
 - `update_membership`
 - `update_membership_locked`

When we are processing a `/backfill` request from a remote server, exclude any
outliers from consideration early on. We can't return outliers anyway (since we
don't know the state at the outlier), and filtering them out earlier means that
we won't attempt to calulate the state for them.

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

HAproxy reverse proxy guide update to stop sending IPv4-mapped address to HS.

This should speed up push rule calculations for rooms with large numbers of local users when the main push rule cache fails.

Co-authored-by: reivilibre <oliverw@matrix.org>

It is currently rather hard to see which rooms are causing inbound federation
traffic. Add the room id to the logs.

Refactor `create_new_client_event` to use a new parameter, `state_event_ids`, which accurately describes the usage with MSC2716 instead of abusing `auth_event_ids` (#12083)

Spawned from https://github.com/matrix-org/synapse/pull/10975#discussion_r813183430

Part of [MSC2716](https://github.com/matrix-org/matrix-spec-proposals/pull/2716)

Hopefully this fixes #12257.

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

Co-authored-by: Shay <hillerys@element.io>

The `MockHttpResource` and `MockKey` objects were unused
since #9396 (74af356b).

as 3.1.0 removed the deprecated jinja2.Markup class which we still rely on.

This reverts commit 8810c93e.

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

Filter the events returned from `/relations` for the requester's ignored users
in a similar way to `/messages` (and `/sync`).

Resolves #10339

Signed-off-by: Nicolas Werner <n.werner@famedly.com>

Co-authored-by: reivilibre <olivier@librepush.net>