Cross-signing fixes, notifications via sync, federation (#1974)

* Initial work on signing key update EDUs

* Fix build

* Produce/consume EDUs

* Producer logging

* Only produce key change notifications for local users

* Better naming

* Try to notify sync

* Enable feature

* Use key change topic

* Don't bother verifying signatures, validate key lengths if we can, notifier fixes

* Copyright notices

* Remove tests from whitelist until matrix-org/sytest#1117

* Some review comment fixes

* Update to matrix-org/gomatrixserverlib@f9416ac

* Remove unneeded parameter

eduserver/api/types.go

@@ -0,0 +1,59 @@
+// Copyright 2021 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package api
+
+import "github.com/matrix-org/gomatrixserverlib"
+
+const (
+	MSigningKeyUpdate = "m.signing_key_update"
+)
+
+type TypingEvent struct {
+	Type   string `json:"type"`
+	RoomID string `json:"room_id"`
+	UserID string `json:"user_id"`
+	Typing bool   `json:"typing"`
+}
+
+type ReceiptEvent struct {
+	UserID    string                      `json:"user_id"`
+	RoomID    string                      `json:"room_id"`
+	EventID   string                      `json:"event_id"`
+	Type      string                      `json:"type"`
+	Timestamp gomatrixserverlib.Timestamp `json:"timestamp"`
+}
+
+type FederationReceiptMRead struct {
+	User map[string]FederationReceiptData `json:"m.read"`
+}
+
+type FederationReceiptData struct {
+	Data     ReceiptTS `json:"data"`
+	EventIDs []string  `json:"event_ids"`
+}
+
+type ReceiptMRead struct {
+	User map[string]ReceiptTS `json:"m.read"`
+}
+
+type ReceiptTS struct {
+	TS gomatrixserverlib.Timestamp `json:"ts"`
+}
+
+type CrossSigningKeyUpdate struct {
+	MasterKey      *gomatrixserverlib.CrossSigningKey `json:"master_key,omitempty"`
+	SelfSigningKey *gomatrixserverlib.CrossSigningKey `json:"self_signing_key,omitempty"`
+	UserID         string                             `json:"user_id"`
+}