Work on MSC2716: matrix-org/matrix-spec-proposals#2716

…'t expect to sync

Split out from #68

…history

…history

 - Seems like the `Volumes` syntax is to create an anonymous volume, https://stackoverflow.com/a/58916037/796832
 - And lots of people not knowing what `Volumes` syntax is or what to do. Seems like Mounts is the thing to use
    - fsouza/go-dockerclient#155
    - https://stackoverflow.com/questions/55718603/golang-docker-library-mounting-host-directory-volumes
    - https://stackoverflow.com/questions/48470194/defining-a-mount-point-for-volumes-in-golang-docker-sdk

…history

…history

…history

…history

See explanation in matrix-org/synapse#9247 (comment)

> Basically, for initial sync we will return the latest N events, which can involve backfilled events, e.g. if you have a graph `A2 -> A1 -> B1 -> B2 -> B3` where An are "live" events and Bn are backfilled events (i.e. the server only has two live events, the rest are backfilled) then initial sync will return `A1`, `A2` and then a bunch of the backfilled events (up to the limit). Incremental syncs from that, however, will just return new events non-backfilled events received after `A2`.
>
> So I'm wondering if your tests are correctly seeing some backfilled events, due to the server not having enough non-backfilled recent events to fill up the timeline section in the initial sync

… the insert point

See matrix-org/synapse#9247 (comment)

As described in matrix-org/matrix-spec-proposals#2716 (comment)

… skip all the auth stuff

Conflicts:
	dockerfiles/synapse/homeserver.yaml

…s who are already in the room

…org/complement into eric/msc2716-backfilling-history

See https://github.com/matrix-org/synapse/blob/develop/CHANGES.md#synapse-1320-2021-04-20

Conflicts:
	dockerfiles/synapse/workers-shared.yaml
	internal/client/client.go
	tests/msc2403_test.go

See 3acc9bb

The name conflict would result in the following error when some alice tests ran before the MSC2716 tests.
```
=== RUN   TestBackfillingHistory
    msc2716_test.go:54: Deploy times: 18.499364ms blueprints, 1.581230486s containers
    msc2716_test.go:60: Deployment.Client - HS name 'hs1' - user ID '@the-bridge-user:hs1' not found
```

See #68 (comment)

This reverts commit dcd84ad.

Add tests for matrix-org/synapse#10276

Also removes the `?user_id` usage because it's no longer necessary.
We now create the proper requester in Synapse for each given sender
in the event.

See #68 (comment)

Before:

```
=== CONT  TestBackfillingHistory
    client.go:356: GET /_matrix/client/r0/sync => 200 OK (31.496008ms)
    client.go:356: POST /_matrix/client/unstable/org.matrix.msc2716/rooms/!GkmAGvcDmllsuqLgZA:hs1/batch_send => 200 OK (96.308307ms)
    client.go:356: POST /_matrix/client/r0/join/!GkmAGvcDmllsuqLgZA:hs1 => 200 OK (808.747133ms)
    client.go:356: GET /_matrix/client/r0/rooms/!GkmAGvcDmllsuqLgZA:hs1/messages => 200 OK (83.415512ms)
```

After:
```
=== CONT  TestBackfillingHistory
    client.go:357: GET hs1/_matrix/client/r0/sync => 200 OK (29.885812ms)
    client.go:357: POST hs1/_matrix/client/unstable/org.matrix.msc2716/rooms/!jbwgZJKNOedwNWRdop:hs1/batch_send => 200 OK (96.173807ms)
    client.go:357: POST hs2/_matrix/client/r0/join/!jbwgZJKNOedwNWRdop:hs1 => 200 OK (808.849665ms)
    client.go:357: GET hs2/_matrix/client/r0/rooms/!jbwgZJKNOedwNWRdop:hs1/messages => 200 OK (73.667196ms)
```

See #68 (comment)