Add a new "vault monitor" command (#8477)

Add a new "vault monitor" command

Co-authored-by: ncabatoff <ncabatoff@hashicorp.com>
Co-authored-by: Calvin Leung Huang <cleung2010@gmail.com>
Co-authored-by: Jeff Mitchell <jeffrey.mitchell@gmail.com>

command/commands.go

@@ -667,6 +667,12 @@ func initCommands(ui, serverCmdUi cli.Ui, runOpts *RunOptions) {
 				BaseCommand: getBaseCommand(),
 			}, nil
 		},
+		"monitor": func() (cli.Command, error) {
+			return &MonitorCommand{
+				BaseCommand: getBaseCommand(),
+				ShutdownCh:  MakeShutdownCh(),
+			}, nil
+		},
 	}
 }