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/utils/license_public_key.go

@@ -0,0 +1,10 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+//go:build !testlicensekey
+
+package utils
+
+import _ "embed"
+
+//go:embed license-public-key.txt
+var publicKey []byte