Includes mmctl into the mono-repo (#23091)

* Includes mmctl into the mono-repo

* Update to use the new public module paths

* Adds docs check to the mmctl CI

* Fix public utils import path

* Tidy up modules

* Fix linter

* Update CI tasks to use the new file structure

* Update CI references

server/cmd/mmctl/commands/docs.go

@@ -0,0 +1,48 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package commands
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/cobra/doc"
+)
+
+var DocsCmd = &cobra.Command{
+	Use:   "docs",
+	Short: "Generates mmctl documentation",
+	Args:  cobra.NoArgs,
+	RunE:  docsCmdF,
+}
+
+func init() {
+	DocsCmd.Flags().StringP("directory", "d", "docs", "The directory where the docs would be generated in.")
+
+	RootCmd.AddCommand(DocsCmd)
+}
+
+func docsCmdF(cmd *cobra.Command, args []string) error {
+	outDir, _ := cmd.Flags().GetString("directory")
+	fileInfo, err := os.Stat(outDir)
+
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return err
+		}
+		if createErr := os.Mkdir(outDir, 0755); createErr != nil {
+			return createErr
+		}
+	} else if !fileInfo.IsDir() {
+		return fmt.Errorf(fmt.Sprintf("File \"%s\" is not a directory", outDir))
+	}
+
+	err = doc.GenReSTTree(RootCmd, outDir)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}