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/cluster_discovery.go

@@ -0,0 +1,17 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package app
+
+func (s *Server) IsLeader() bool {
+	return s.platform.IsLeader()
+}
+
+func (a *App) IsLeader() bool {
+	return a.Srv().IsLeader()
+}
+
+func (a *App) GetClusterId() string {
+
+	return a.Srv().Platform().GetClusterId()
+}