Adds a new method, check_3pid_auth, which gives password providers
the chance to allow authentication with third-party identifiers such
as email or msisdn.
`__str__` depended on `self.addr`, which was absent from
ClientReplicationStreamProtocol, so attempting to call str on such an object
would raise an exception.
We can calculate the peer addr from the transport, so there is no need for addr
anyway.
As per #3622, we remove trailing slashes from outbound federation requests. However, to ensure that we remain backwards compatible with previous versions of Synapse, if we receive a HTTP 400 with `M_UNRECOGNIZED`, then we are likely talking to an older version of Synapse in which case we retry with a trailing slash appended to the request path.
There are a number of instances where a server or admin may puppet a
user to join/leave rooms, which we don't want to fail if the user has
not consented to the privacy policy. We fix this by adding a check to
test if the requester has an associated access_token, which is used as a
proxy to answer the question of whether the action is being done on
behalf of a real request from the user.
Rather than using a Mock for the homeserver config, use a genuine
HomeServerConfig object. This makes for a more realistic test, and means that
we don't have to keep remembering to add things to the mock config every time
we add a new config setting.
Make it so that most options in the config are optional, and commented out in
the generated config.
The reasons this is a good thing are as follows:
* If we decide that we should change the default for an option, we can do so,
and only those admins that have deliberately chosen to override that option
will be stuck on the old setting.
* It moves us towards a point where we can get rid of the super-surprising
feature of synapse where the default settings for the config come from the
generated yaml.
* It makes setting up a test config for unit testing an order of magnitude
easier (see forthcoming PR).
* It makes the generated config more consistent, and hopefully easier for users
to understand.
