This will help mitigating any discrepancies between the issuer
configured and the one returned by the OIDC provider.

This also removes the need for configuring the `account_management_url`
explicitely, as it will now be loaded from the OIDC discovery, as per
MSC2965.

Because we may now fetch stuff for the .well-known/matrix/client
endpoint, this also transforms the client well-known resource to be
asynchronous.

Rather than 501 M_UNRECOGNISED

Client side implementation at
https://github.com/matrix-org/matrix-react-sdk/pull/12892/

Based on #17600

---------

Co-authored-by: Eric Eastwood <eric.eastwood@beta.gouv.fr>

This is so that we can cache it.

We also move the sliding sync types to
`synapse/types/handlers/sliding_sync.py`. This is mainly in-prep for

The only change in behaviour is that
`RoomSyncConfig.combine_sync_config(..)` now returns a new room sync
config rather than mutating in-place.

Reviewable commit-by-commit.

---------

Co-authored-by: Eric Eastwood <eric.eastwood@beta.gouv.fr>

When returning receipts in sliding sync for initial rooms we should
always include our own receipts in the room (even if they don't match
any timeline events).

Reviewable commit-by-commit.

---------

Co-authored-by: Eric Eastwood <eric.eastwood@beta.gouv.fr>

Otherwise we use the `expected_size` from the initial federation
request, which might be far too low.

### Pull Request Checklist

<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->

* [x] Pull request is based on the develop branch
* [x] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
  - Use markdown where necessary, mostly for `code blocks`.
  - End with either a period (.) or an exclamation mark (!).
  - Start with a capital letter.
- Feel free to credit yourself, by adding a sentence "Contributed by
@github_username." or "Contributed by [Your Name]." to the end of the
entry.
* [x] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct
(run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters)

)

---------

Co-authored-by: Erik Johnston <erikj@element.io>

Move calculating of the room lists out of the core handler. This should
make it easier to switch things around to start using the tables in
#17512.

This is just moving code between files and methods.

Reviewable commit-by-commit

`hash_password` now actually accepts password from stdin. The `getpass`
reads from TTY, and does NOT accept stdin in any way.

The manpage has been updated to reflect that.

The idea is to engineer it so that the vast majority of the rooms can
stay in the cache, so we can just ignore them.

The decorator assumed we were always wrapping function methods

That file was getting long.

The changes are non functional, and simply split things up into:
- the main class
- the connection store
- the extensions
- the types

Let's only pull out the events we care about. Note that the index isn't
necessary here, as postgres is happy to scan the set of rooms for the
events.

This should let us see how quickly we actually process things in
practice.

This supersedes #17503, given the per-connection state is being heavily
rewritten it felt easier to recreate the PR on top of that work.

This correctly handles the case of timeline limits going up and down.

This does not handle changes in `required_state`, but that can be done
as a separate PR.

Based on #17575.

---------

Co-authored-by: Eric Eastwood <eric.eastwood@beta.gouv.fr>

This is to make initial sliding sync a bit faster

Add connection tracking to the receipts extension.

Based on #17574

---------

Co-authored-by: Eric Eastwood <eric.eastwood@beta.gouv.fr>

This is some prep work ahead of correctly tracking receipts, where we
will also want to track the room status in terms of last receipt we had
sent down.

Essentially, we add two classes `PerConnectionState` and a mutable
version, and then operate on those.

---------

Co-authored-by: Eric Eastwood <eric.eastwood@beta.gouv.fr>

Results in:

```
AssertionError: null
  File "synapse/http/server.py", line 332, in _async_render_wrapper
    callback_return = await self._async_render(request)
  File "synapse/http/server.py", line 544, in _async_render
    callback_return = await raw_callback_return
  File "synapse/federation/transport/server/_base.py", line 369, in new_func
    response = await func(
  File "synapse/federation/transport/server/federation.py", line 826, in on_GET
    await self.media_repo.get_local_media(
  File "synapse/media/media_repository.py", line 473, in get_local_media
    await respond_with_multipart_responder(
  File "synapse/media/_base.py", line 353, in respond_with_multipart_responder
    assert content_length is not None
```

This stops people from getting half way through a step and it failing
due to the github token having expired (this happens to me every damn
time).

Follow on from #17537.

This is just adding a batched lookup function (you might want to hide
whitespace in the diff).

So that clients can check for support. Note that if the feature is only
enabled for some users, the `/versions` request must be authenticated to
pick up that SSS is enabled for the user

`old_verify_keys` isn't marked as required in
https://spec.matrix.org/v1.11/server-server-api/#get_matrixkeyv2server
and there's no functional difference between an empty object and
omitting the object, so I don't think there's any reason synapse should
explode when the field is omitted.

Follows on from #17567