Changing Friendica\App\Mode from static methods to public methods

- Changing from static methods to public methods
- Adding dev-composer-dependency Mockery for static method mocking (f.e. Config, DBA)
- Adding ModeTest with Mocking
- removing bootstrap from phpunit.xml because of double loading tests\bootstrap.php

src/Core/Console/PostUpdate.php

@@ -33,7 +33,7 @@ HELP;
 
 	protected function doExecute()
 	{
-		$a = get_app();
+		$a = \Friendica\BaseObject::getApp();
 
 		if ($this->getOption($this->helpOptions)) {
 			$this->out($this->getHelp());
@@ -50,7 +50,7 @@ HELP;
 			return 0;
 		}
 
-		if (App\Mode::isInstall()) {
+		if ($a->getMode()->isInstall()) {
 			throw new \RuntimeException('Database isn\'t ready or populated yet');
 		}