Remove experimental MSC2716 implementation to incrementally import history into existing rooms (#15748)

Context for why we're removing the implementation:

 - https://github.com/matrix-org/matrix-spec-proposals/pull/2716#issuecomment-1487441010
 - https://github.com/matrix-org/matrix-spec-proposals/pull/2716#issuecomment-1504262734

Anyone wanting to continue MSC2716, should also address these leftover tasks: https://github.com/matrix-org/synapse/issues/10737

Closes https://github.com/matrix-org/synapse/issues/10737 in the fact that it is not longer necessary to track those things.

* Fully qualified docker image names for the main Dockerfile and Complement related.

* Fully qualified docker image names for Dockerfiles associated with building Debian release artifacts.

This one is harder and is separate from the other commit in case it wasn't correct or was unwanted. I decided to
do the expansion on the docker images in the Dockerfile itself, instead of the various source places that build
which distribution that is selected, as it would have been more invasive with the scripts breaking up the string
for tagging and such. This one is untested.

* Changelog

* Update docker/Dockerfile-workers

* Update docker/complement/Dockerfile

---------

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

Co-authored-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

Signed-off-by: Jason Little <realtyem@gmail.com>

* Enable Complement tests for Faster Remote Room Joins on worker-mode

* (dangerous) Add an override to allow Complement to use FRRJ under workers

* Newsfile

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

* Fix race where we didn't send out replication notification

* MORE HACKS

* Fix get_un_partial_stated_rooms_token to take instance_name

* Fix bad merge

* Remove warning

* Correctly advance un_partial_stated_room_stream

* Fix merge

* Add another notify_replication

* Fixups

* Create a separate ReplicationNotifier

* Fix test

* Fix portdb

* Create a separate ReplicationNotifier

* Fix test

* Fix portdb

* Fix presence test

* Newsfile

* Apply suggestions from code review

* Update changelog.d/14752.misc

Co-authored-by: Erik Johnston <erik@matrix.org>

* lint

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>
Co-authored-by: Erik Johnston <erik@matrix.org>

Serving partial join responses is no longer experimental. They will only be served under the stable identifier if the the undocumented config flag experimental.msc3706_enabled is set to true.

Synapse continues to request a partial join only if the undocumented config flag experimental.faster_joins is set to true; this setting remains present and unaffected.

Add `--editable` flag to `complement.sh` which uses an editable install of Synapse for faster turn-around times whilst developing iteratively. (#14548)

Co-authored-by: Mathieu Velten <mathieuv@matrix.org>

Fix https://github.com/matrix-org/synapse/issues/14390

 - Client API: `/_matrix/client/unstable/org.matrix.msc3030/rooms/<roomID>/timestamp_to_event?ts=<timestamp>&dir=<direction>` -> `/_matrix/client/v1/rooms/<roomID>/timestamp_to_event?ts=<timestamp>&dir=<direction>`
 - Federation API: `/_matrix/federation/unstable/org.matrix.msc3030/timestamp_to_event/<roomID>?ts=<timestamp>&dir=<direction>` -> `/_matrix/federation/v1/timestamp_to_event/<roomID>?ts=<timestamp>&dir=<direction>`

Complement test changes: https://github.com/matrix-org/complement/pull/559

* Expose getting SYNAPSE_WORKER_TYPES from external, allowing override of workers requested.

* Add WORKER_TYPES variable option to complement.sh script that passes requested workers into start_for_complement.sh entrypoint.

* Update docs to reflect this new ability.

* Changelog

* Don't rely on soft wrapping to format long strings

Good idea dklimpel. Thanks for catching that.

Co-authored-by: Dirk Klimpel <5740567+dklimpel@users.noreply.github.com>

* Small nits just noticed in docs.

* Fixup new line in docs.

Co-authored-by: Dirk Klimpel <5740567+dklimpel@users.noreply.github.com>

Co-authored-by: Eric Eastwood <erice@element.io>

Signed-off-by: Mathieu Velten <mathieuv@matrix.org>
Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

Doing so in the base postgres image doesn't work with buildah because
changes in a declared VOLUME in the Dockerfile is supposed to be
discarded, cf https://docs.docker.com/engine/reference/builder/#volume



Signed-off-by: Mathieu Velten <mathieuv@matrix.org>

Co-authored-by: David Robertson <davidr@element.io>

When building the docker images for complement testing, copy a preinstalled
complement over from a base image, rather than apt installing it. This avoids
network traffic and is much faster.

Improve startup times in Complement test runs against workers, particularly in CPU-constrained environments. (#13127)

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

If no database is configured explicitly, use sqlite.

This means that you don't have to pass any variables into the image.

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

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

Fix Complement `TestCanRegisterAdmin` with workers, by adding Complement's shared registration secret. (#12819)

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

When we join a room via the faster-joins mechanism, we end up with "partial
state" at some points on the event DAG. Many parts of the codebase need to
wait for the full state to load. So, we implement a mechanism to keep track of
which events have partial state, and wait for them to be fully-populated.

... with a bit more verbosity.

Fixes matrix-org/complement#330 (or it will, once we remove the old files).

It's not quite a lift-and-shift: I've also taken the opportunity to get rid of the custom CA that we used to use to sign the TLS certs, which has been superceded by the CA exposed by Complement.