Fix tests

- Fix InstallerTest case
- Fix native function mocking
- Add returntype for Unit-Tests
- Fixing ExtendedPDO test troubles
- Fix wrong class inheritance path for DatabaseTestTrait.php
- Fix SyslogLogger Server Exception for PHP8
- Add user/contact to database.fixture.php
- Avoid invalid rollbacks for test setup in PHP8

tests/MockedTest.php

@@ -28,7 +28,7 @@ use PHPUnit\Framework\TestCase;
  */
 abstract class MockedTest extends TestCase
 {
-	protected function tearDown()
+	protected function tearDown() : void
 	{
 		\Mockery::close();