Remove unused Prometheus recording rules from `synapse-v2.rules` and add comments describing where the rest are used. (#13756)

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

Update the docstrings for `get_users_in_room` and
`get_current_hosts_in_room` to explain the impact of partial state.

Signed-off-by: Sean Quah <seanq@matrix.org>

Handle malformed user IDs with no colons in `get_current_hosts_in_room`.
It's not currently possible for a malformed user ID to join a room, so
this error would never be hit.

Signed-off-by: Sean Quah <seanq@matrix.org>

Previously, `is_mine_id` would raise an exception when passed an ID with
no colons. Return `False` instead.

Fixes #13040.

Signed-off-by: Sean Quah <seanq@matrix.org>

When backfilling, `_get_state_ids_after_missing_prev_event` calls [`get_metadata_for_events`](https://github.com/matrix-org/synapse/blob/26bc26586b4b95d63ce7e453e9312469843f796e/synapse/handlers/federation_event.py#L1133). For `#matrix:matrix.org`, it's called with 77k `state_events` which means 77 calls to the database and takes 28 seconds.

Rename the `EventFormatVersions` enum values so that they line up with room version numbers. (#13706)

This adds two new admin APIs that allow us to fetch messages from a room within a particular time.

This is a re-do of 57d334a1 (#13365),
which was backed out in 12abd724 (#13501).

The `room_id` field represented the parent space for each room
and was made redundant by changes in the API shape where the
`children_state` is now nested underneath each `room`.

The room ID of each child is in the `state_key` field and is still
available.

Removes the ability to configure legacy direct TCP replication. Workers now require Redis to run.

* Reduce number of CI jobs run on PRs

* Newsfile

* Also limit sytest jobs

* Fix typo

* Fix up

* Fixup

Extend the release script to wait for GitHub Actions to finish and to be usable as a guide for the whole process. (#13483)

Summarized from @richvdh's reply at https://github.com/matrix-org/synapse/pull/13589#discussion_r961116999

It was really easy to miss the `enable_metrics: True` step with the previous language.

Otherwise they'll be leaked due to the filtering code only respecting
the stable identifiers for private read receipts.

This avoids doing work that will never be used (since the
resulting unread counts will never be sent in a /sync
response).

The negative of doing this is that unread counts will be
incorrect when the feature is initially enabled.

* Add missing graph to contrib

* Update with minor but plausible changes, including positioning changes

* Newsfile

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

Fixes #13613.

* Add monthly active users documentation

* changelog

* Tidy up notes

* more tidyup

* Rewrite #1

* link back to mau docs

* fix links

* s/appservice|AS/application service

* further review

* a newline

* Remove bit about shadow banned users.

I think talking about them is confusing, and the current text doesn't imply they get any special treatment.

* Update docs/usage/administration/monthly_active_users.md

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

* Update docs/usage/administration/monthly_active_users.md

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

Co-authored-by: Brendan Abolivier <babolivier@matrix.org>
Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>