Refactor dynamic App::getMode() to static DI::mode()

src/App.php

@@ -155,16 +155,6 @@ class App
 		return $this->config->getCache()->get('system', 'basepath');
 	}
 
-	/**
-	 * Returns the Mode of the Application
-	 *
-	 * @return App\Mode The Application Mode
-	 */
-	public function getMode()
-	{
-		return $this->mode;
-	}
-
 	/**
 	 * Returns the Database of the Application
 	 *