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/src/Util/Emailer/MailBuilderTest.php

@@ -51,7 +51,7 @@ class MailBuilderTest extends MockedTest
 	/** @var string */
 	private $defaultHeaders;
 
-	protected function setUp()
+	protected function setUp(): void
 	{
 		parent::setUp();
 

tests/src/Util/Emailer/SystemMailBuilderTest.php

@@ -41,7 +41,7 @@ class SystemMailBuilderTest extends MockedTest
 	/** @var BaseURL */
 	private $baseUrl;
 
-	protected function setUp()
+	protected function setUp(): void
 	{
 		parent::setUp();