Part of my continuing quest to make the docker images build quicker: copy nginx and redis in from base docker images, rather than apt installing each time.

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

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.

Add the ability to set the log level using the `SYNAPSE_TEST_LOG_LEVEL` environment when using `complement.sh`. (#13152)

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>

Refactor the Dockerfile-workers configuration script to use Jinja2 templates in Synapse workers' Supervisord blocks. (#13054)

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)

* Bump the HS startup timeout
* Log prefixes for more processes
* Bump the overall timeout

Add the `notify_appservices_from_worker` configuration option (superseding `notify_appservices`) to allow a generic worker to be designated as the worker to send traffic to Application Services. (#12452)

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

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

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.

This is an attempt to reduce the rebuild time. In short, we reduce the amount
of stuff that the dockerfile installs, so as to give a faster startup.

... with a bit more verbosity.

When we run a worker-mode synapse under docker, everything gets logged to stdout. Currently, output from the workers is tacked with a worker name, for example:

```
2022-04-13 15:27:56,810 - worker:frontend_proxy1 - synapse.util.caches.lrucache - 154 - INFO - LruCache._expire_old_entries-0 - Dropped 0 items from caches
```

- note `worker:frontend_proxy1`. No such tag is applied to log lines from the master, which makes somewhat confusing reading.

To fix this, we generate a dedicated log config file for the master in the same way that we do for the workers, and use that.

The requirements file generated by `poetry export` isn't correctly processed by `pip install -r requirements.txt`. It contains twisted and treq, both pinned to 22.2.0.

When `pip` installs treq, it notices that `Twisted[tls]` is required. It then tries to acquire the latest twisted release, only to fail (because this hash isn't listed in the requirements file).From e.g. https://github.com/matrix-org/synapse/runs/5977154990?check_suite_focus=true

> ```
> #15 9.204 Collecting Twisted[tls]>=18.7.0
> #15 9.205 ERROR: In --require-hashes mode, all requirements must have their versions pinned with ==. These do not:
> #15 9.205     Twisted[tls]>=18.7.0 from https://files.pythonhosted.org/packages/db/99/38622ff95bb740bcc991f548eb46295bba62fcb6e907db1987c4d92edd09/Twisted-22.4.0-py3-none-any.whl#sha256=f9f7a91f94932477a9fc3b169d57f54f96c6e74a23d78d9ce54039a7f48928a2 (from treq==22.2.0->-r /synapse/requirements.txt (line 724))
> #15 ERROR: executor failed running [/bin/sh -c pip install --prefix="/install" --no-warn-script-location -r /synapse/requirements.txt]: exit code: 1
> ```

The underlying pip issue is https://github.com/pypa/pip/issues/9644. A comment notes that one can avoid this behaviour with by `pip install`ing with the `--no-deps` flag. Let us do so.

(At first glance, the problem looks like https://github.com/python-poetry/poetry/issues/5311, but that was a bug in `poetry install`; this is `poetry export`, whose behaviour is fine AFAICS).

This wasn't quite generating the right thing.

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.