Refactor template engine code

- Convert ITemplateEngine interface to abstract class
- Remove dependency to App in FriendicaSmarty and FriendicaSmartyEngine
- Normalize replaceMacro parameter behavior using Smarty template string prefixes
- Remove obsolete FriendicaSmarty->parsed method
- Update unused Smarty directory paths

src/Render/ITemplateEngine.php

@@ -1,31 +0,0 @@
-<?php
-/**
- * @copyright Copyright (C) 2020, Friendica
- *
- * @license GNU AGPL version 3 or any later version
- *
- * This program 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.
- *
- * This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
- *
- */
-
-namespace Friendica\Render;
-
-/**
- * Interface for template engines
- */
-interface ITemplateEngine
-{
-	public function replaceMacros($s, $v);
-	public function getTemplateFile($file, $subDir = '');
-}