Complete translation directory exclusion list, make it more readable

[MAILPOET-4611]

mailpoet/RoboFile.php

@@ -117,10 +117,27 @@ class RoboFile extends \Robo\Tasks {
   }
 
   public function translationsBuild() {
+    $exclude = implode(',', [
+      '.mp_svn',
+      'generated',
+      'lang',
+      'lib-3rd-party',
+      'mailpoet-premium',
+      'node_modules',
+      'plugin_repository',
+      'prefixer',
+      'tasks',
+      'temp',
+      'tests',
+      'tools',
+      'vendor',
+      'vendor-prefixed',
+    ]);
+
     $this->collectionBuilder()
       ->taskExec('mkdir -p ' . __DIR__ . '/lang')
       ->taskExec(
-        'php -d memory_limit=-1 tasks/makepot/grunt-makepot.php wp-plugin . lang/mailpoet.pot mailpoet .mp_svn,assets,lang,node_modules,plugin_repository,tasks,tests,vendor'
+        "php -d memory_limit=-1 tasks/makepot/grunt-makepot.php wp-plugin . lang/mailpoet.pot mailpoet $exclude"
       )->run();
   }