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/Core/Lock/APCuCacheLockTest.php

@@ -29,7 +29,7 @@ use Friendica\Core\Lock\CacheLock;
  */
 class APCuCacheLockTest extends LockTest
 {
-	protected function setUp()
+	protected function setUp(): void
 	{
 		if (!APCuCache::isAvailable()) {
 			static::markTestSkipped('APCu is not available');