This doesn't cover *all* of the registration flows, but it does cover the most
common ones: in particular: shared_secret registration, appservice
registration, and normal user/pass registration.
Pull device_id from the registration parameters. Register the device in the
devices table. Associate the device with the returned access and refresh
tokens. Profit.
* `RegistrationHandler.appservice_register` no longer issues an access token:
instead it is left for the caller to do it. (There are two of these, one in
`synapse/rest/client/v1/register.py`, which now simply calls
`AuthHandler.issue_access_token`, and the other in
`synapse/rest/client/v2_alpha/register.py`, which is covered below).
* In `synapse/rest/client/v2_alpha/register.py`, move the generation of
access_tokens into `_create_registration_details`. This means that the normal
flow no longer needs to call `AuthHandler.issue_access_token`; the
shared-secret flow can tell `RegistrationHandler.register` not to generate a
token; and the appservice flow continues to work despite the above change.
This is meant to be an *almost* non-functional change, with the exception that
it fixes what looks a lot like a bug in that it only calls
`auth_handler.add_threepid` and `add_pusher` once instead of three times.
The idea is to move the generation of the `access_token` out of
`registration_handler.register`, because `access_token`s now require a
device_id, and we only want to generate a device_id once registration has been
successful.
V2 Registration forced everyone (including ASes) to create a password for a
user, when ASes should be able to omit passwords. Also unbreak AS registration
in general which checked too early if the given username was claimed by an AS;
it was checked before knowing if the AS was the one doing the registration! Add
unit tests for AS reg, user reg and disabled_registration flag.
