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/random.go

@@ -0,0 +1,20 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package utils
+
+import (
+	"math/rand"
+)
+
+type Range struct {
+	Begin int
+	End   int
+}
+
+func RandIntFromRange(r Range) int {
+	if r.End-r.Begin <= 0 {
+		return r.Begin
+	}
+	return rand.Intn((r.End-r.Begin)+1) + r.Begin
+}