Make Router::getModuleClass throw exceptions

- Add new MethodNotAllowedModule
- Add new Module->determineClass catch blocks
- Update Module and Router tests

src/Module/PageNotFound.php

@@ -1,15 +0,0 @@
-<?php
-
-namespace Friendica\Module;
-
-use Friendica\BaseModule;
-use Friendica\Core\L10n;
-use Friendica\Network\HTTPException;
-
-class PageNotFound extends BaseModule
-{
-	public static function content()
-	{
-		throw new HTTPException\NotFoundException(L10n::t('Page not found.'));
-	}
-}