Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/channels/app/plugin_event.go

@@ -0,0 +1,22 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package app
+
+import (
+	"encoding/json"
+
+	"github.com/mattermost/mattermost-server/v6/model"
+)
+
+func (ch *Channels) notifyClusterPluginEvent(event model.ClusterEvent, data model.PluginEventData) {
+	buf, _ := json.Marshal(data)
+	if ch.srv.platform.Cluster() != nil {
+		ch.srv.platform.Cluster().SendClusterMessage(&model.ClusterMessage{
+			Event:            event,
+			SendType:         model.ClusterSendReliable,
+			WaitForAllToSend: true,
+			Data:             buf,
+		})
+	}
+}