Fixes #5905

Prune old rows in user_ips tables.

Move last seen info into devices table

Enable cleaning up extremities with dummy events by default to prevent undue build up of forward extremities. (#5884)

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

Fixes #6103

If email or msisdn verification aren't supported, let's stop advertising them
for registration.

Fixes #6100.

Pull the checkers out to their own classes, rather than having them lost in a
massive 1000-line class which does everything.

This is also preparation for some more intelligent advertising of flows, as per #6100

because, frankly, it looked like it was written by an axe-murderer.

This should be a non-functional change, except that where `m.login.dummy` was
previously advertised *before* `m.login.terms`, it will now be advertised
afterwards. AFAICT that should have no effect, and will be more consistent with
the flows that involve passing a 3pid.

Fix the return value in the users_set_deactivated_flag background job

Update the process for mapping SAML2 users to matrix IDs

Added in #5377, apparently in error

Defaults to pruning everything older than 28d.

This allows checking if a specific background update has completed.

This does the same thing as `run_as_background_process` but means we
don't need to create superfluous functions.

Fix a bug with saml attribute maps.

Second part of solving #6076
Fixes #6076

We return a submit_url parameter on calls to POST */msisdn/requestToken so that clients know where to submit token information to.

Add a m.separate_add_and_bind flag set to True. See MSC2290's Backward Compatibility section for details.

Make the sample saml config closer to our standards

Uses a SimpleHttpClient instance equipped with the federation_ip_range_blacklist list for requests to identity servers provided by user input. Does not use a blacklist when contacting identity servers specified by account_threepid_delegates. The homeserver trusts the latter and we don't want to prevent homeserver admins from specifying delegates that are on internal IP addresses.

Fixes #5935

Adds a flag to /versions' unstable_features section indicating that this Synapse understands what an id_access_token is, as per MSC2264.

Fixes #5927

As MSC2263 states, m.require_identity_server must be set to false when it does not require an identity server to be provided by the client for the purposes of email registration or password reset.

Adds an m.require_identity_server flag to /versionss unstable_flags section. This will advertise that Synapse no longer needs id_server as a parameter.

First part of solving #6076