this hasn't done anything for years

- Put the default window_size back to 1000ms (broken by #5181)
- Make the `rc_federation` config actually do something
- fix an off-by-one error in the 'concurrent' limit
- Avoid creating an unused `_PerHostRatelimiter` object for every single
  incoming request

The runtime errors that dealt with local email password resets talked about config options that users may not even have in their config file yet (if upgrading). Instead, the cryptic errors are now replaced with hopefully much more helpful ones.

* Improve the backwards compatibility re-exports of synapse.logging.context.

* reexport logformatter too

* Add a sytest blacklist file

* Add changelog

* Add blacklist to manifest

Suggest people use a config file for Docker instead of env vars

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

* Fix 'utime went backwards' errors on daemonization.

Fixes #5608

* remove spurious debug

Fixes #5602, #5603

Removes any `SMTP_*` docker container environment variables from having any effect on the default config.

Fixes https://github.com/matrix-org/synapse/issues/5430

* SAML2 Improvements and redirect stuff

Signed-off-by: Alexander Trost <galexrt@googlemail.com>

* Code cleanups and simplifications.

Also: share the saml client between redirect and response handlers.

* changelog

* Revert redundant changes to static js

* Move all the saml stuff out to a centralised handler

* Add support for tracking SAML2 sessions.

This allows us to correctly handle `allow_unsolicited: False`.

* update sample config

* cleanups

* update sample config

* rename BaseSSORedirectServlet for consistency

* Address review comments

Fix --no-daemonize flag for synctl

Signed-off-by: Amir Zarrinkafsh <nightah@me.com>

Signed-off-by: Pau Rodriguez-Estivill <prodrigestivill@gmail.com>

Fixes #5582

Fix sync tightloop bug.