Add "valet stop dnsmasq" option

Fixes #1419

Adds:
- `valet stop dnsmasq`
- `valet stop all` (which includes php, nginx, dnsmasq)
- When `valet stop` is called without a service name, a message indicates that dnsmasq can also be stopped via `valet stop dnsmasq`
- Aside: phpfpm now also displays a message when stopping; previously it was silent.

cli/Valet/DnsMasq.php

@@ -47,6 +47,14 @@ public function uninstall(): void
         $this->files->unlink($this->resolverPath.'/'.$tld);
     }
 
+    /**
+     * Stop the dnsmasq service.
+     */
+    public function stop(): void
+    {
+        $this->brew->stopService(['dnsmasq']);
+    }
+
     /**
      * Tell Homebrew to restart dnsmasq.
      */