Signed-off-by: Daniel Hoffend <dh@dotlan.net>

Helps address #5444

Fixes #5533

Adds information about how to install and run black on the codebase.

This is helpful when generating a config file for running synapse under docker.

Because sticking it in the same place as the config isn't necessarily the right
thing to do.

This has no useful purpose on python3, and is generally a source of confusion.

E_TOO_MANY_NEGATIVES

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

Add FAQ questions to federate.md. Add a health warning making it clear that the 1711 upgrade FAQ is now out of date.

Set default room version to v4.

Sends password reset emails from the homeserver instead of proxying to the identity server. This is now the default behaviour for security reasons. If you wish to continue proxying password reset requests to the identity server you must now enable the email.trust_identity_server_for_password_resets option.

This PR is a culmination of 3 smaller PRs which have each been separately reviewed:

* #5308
* #5345
* #5368

There are a few changes going on here:

* We make checking the signature on a key server response optional: if no
  verify_keys are specified, we trust to TLS to validate the connection.

* We change the default config so that it does not require responses to be
  signed by the old key.

* We replace the old 'perspectives' config with 'trusted_key_servers', which
  is also formatted slightly differently.

* We emit a warning to the logs every time we trust a key server response
  signed by the old key.

1.0 upgrade/install notes

fixes #4951

Improve documentation of monthly active user blocking and mau_trial_days

These new rules allow a user to instead route only matrix traffic, allowing them to run matrix on the domain without affecting their existing websites

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

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

Replaces DEFAULT_ROOM_VERSION constant with a method that first checks the config, then returns a hardcoded value if the option is not present.

That hardcoded value is now located in the server.py config file.

* Stop telling people to install the optional dependencies.

They're optional.

Also update the postgres docs a bit for clarity(?)

Signed-off-by: Gergely Polonkai <gergely@polonkai.eu>