Introduce new DI container

- Adding Friendica\DI class for getting dynamic classes
- Replacing BaseObject::getApp() with this class

src/Module/WellKnown/NodeInfo.php

@@ -4,6 +4,7 @@ namespace Friendica\Module\WellKnown;
 
 use Friendica\App;
 use Friendica\BaseModule;
+use Friendica\DI;
 
 /**
  * Standardized way of exposing metadata about a server running one of the distributed social networks.
@@ -13,7 +14,7 @@ class NodeInfo extends BaseModule
 {
 	public static function rawContent(array $parameters = [])
 	{
-		$app = self::getApp();
+		$app = DI::app();
 
 		self::printWellKnown($app);
 	}