Move Permission Set over to DDD

- Add Permission Set Repository, Model and Collection
- Mark static PermissionSet method as deprecated

src/Collection/PermissionSets.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace Friendica\Collection;
+
+use Friendica\BaseCollection;
+
+class PermissionSets extends BaseCollection
+{
+
+}