[ATTACHMENTS] Further refactoring

Some key points:
- Components and Plugins shouldn't extend Module directly
- Avatars should be fetched via GSActor ID, not by nickname as that isn't unique
- Avatar now is a separate Component
- Common file utilities are now to be placed in Core\GSFile, this will
  handle storage and trigger validation
- Some bug fixes

components/Avatar/Controller/Avatar.php

@@ -0,0 +1,44 @@
+<?php
+
+// {{{ License
+
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// GNU social is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+// }}}
+
+namespace Component\Avatar\Controller;
+
+use App\Core\Controller;
+use App\Core\GSFile as M;
+use Exception;
+use Symfony\Component\HttpFoundation\Request;
+
+class Avatar extends Controller
+{
+    /**
+     * @throws Exception
+     */
+    public function avatar(Request $request, int $gsactor_id, string $size)
+    {
+        switch ($size) {
+            case 'full':
+                $res = \Component\Avatar\Avatar::getAvatarFileInfo($gsactor_id);
+                return M::sendFile($res['file_path'], $res['mimetype'], $res['title']);
+            default:
+                throw new Exception('Not implemented');
+        }
+    }
+}