Add documentation for the spam checker.

Update documentation to reflect the correct format of user_id (fully qualified).

As using non-C locale can cause issues on upgrading OS.

Signed-off-by: Jason Robinson <jasonr@matrix.org>

* Add note that user_dir requires disabling user dir
  updates from the main synapse process.
* Add note that federation_reader should have
  the federation listener resource.

Signed-off-by: Jason Robinson <jasonr@matrix.org>

This will be used to retry outbound transactions to a remote server if
we think it might have come back up.

Generally try to make this more comprehensible, and make it match the
conventions.

I've removed the documentation for all the settings which allow you to change
the names of the template files, because I can't really see why they are
useful.

Signed-off-by: Manuel Stahl <manuel.stahl@awesome-technologies.de>

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

Have a purge job running every 5min is probably not something we want to advise admins to do as a sort-of default.

This looks like it got half-killed back in #888.

Fixes #6567.

put the 2nd part of the "source installation"-section into a new section, because it also applies to Debian packages

* Remove sections of federate.md explaining delegation at time of Synapse 1.0 transition

Signed-off-by: Aaron Raimist <aaron@raim.ist>

* Add changelog

Signed-off-by: Aaron Raimist <aaron@raim.ist>

TODO: automate generation of this

I want to do some key rotation, and it is silly that we don't have a way to do
this.