Handle guest access [1/2?] (#2872)

Needs https://github.com/matrix-org/sytest/pull/1315, as otherwise the
membership events aren't persisted yet when hitting `/state` after
kicking guest users.

Makes the following tests pass:
```
Guest users denied access over federation if guest access prohibited
Guest users are kicked from guest_access rooms on revocation of guest_access
Guest users are kicked from guest_access rooms on revocation of guest_access over federation
```

Todo (in a follow up PR):
- Restrict access to CS API Endpoints as per
https://spec.matrix.org/v1.4/client-server-api/#client-behaviour-14

Co-authored-by: kegsay <kegan@matrix.org>

roomserver/internal/input/input.go

@@ -23,6 +23,8 @@ import (
 	"sync"
 	"time"
 
+	userapi "github.com/matrix-org/dendrite/userapi/api"
+
 	"github.com/Arceliar/phony"
 	"github.com/getsentry/sentry-go"
 	"github.com/matrix-org/gomatrixserverlib"
@@ -79,6 +81,7 @@ type Inputer struct {
 	JetStream           nats.JetStreamContext
 	Durable             nats.SubOpt
 	ServerName          gomatrixserverlib.ServerName
+	SigningIdentity     *gomatrixserverlib.SigningIdentity
 	FSAPI               fedapi.RoomserverFederationAPI
 	KeyRing             gomatrixserverlib.JSONVerifier
 	ACLs                *acls.ServerACLs
@@ -87,6 +90,7 @@ type Inputer struct {
 	workers             sync.Map // room ID -> *worker
 
 	Queryer *query.Queryer
+	UserAPI userapi.RoomserverUserAPI
 }
 
 // If a room consumer is inactive for a while then we will allow NATS