Moved Application::$controllerNamespace init into variable declaration, reordered Module::__construct.

when error occurs while handling errors output was not readable in web
context

This reverts commit 9d7597d6, reversing
changes made to 6b6390f7.

Result of a discussion with @qiangxue
- there is not global Yii::$app->response anymore, every action has
  dedicated response class
- implementation allows using HMVC pattern now, nested actions do not
  interfer