refactor: update code base to php 8 and set phpstan lvl to 6

app/Controllers/Admin/FediverseController.php

app/Controllers/Admin/HomeController.php

app/Controllers/Admin/MyAccountController.php

app/Controllers/Admin/PageController.php

app/Controllers/Admin/PersonController.php

app/Controllers/Admin/PodcastController.php

app/Controllers/Admin/PodcastImportController.php

app/Controllers/Admin/PodcastPersonController.php

app/Controllers/Admin/PodcastPlatformController.php

app/Controllers/Admin/UserController.php

app/Controllers/AuthController.php

app/Controllers/BaseController.php

app/Controllers/EpisodeController.php

app/Controllers/HomeController.php

app/Controllers/InstallController.php

app/Controllers/NoteController.php

app/Controllers/PageController.php

app/Controllers/PodcastController.php

app/Database/Seeds/FakePodcastsAnalyticsSeeder.php

app/Entities/Actor.php