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/cmd/mattermost/commands/exec_command_test.go

@@ -0,0 +1,19 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package commands
+
+import (
+	"flag"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestExecCommand(t *testing.T) {
+	if filter := flag.Lookup("test.run").Value.String(); filter != "ExecCommand" {
+		t.Skip("use -run ExecCommand to execute a command via the test executable")
+	}
+	RootCmd.SetArgs(flag.Args())
+	require.NoError(t, RootCmd.Execute())
+}