More PHP 8.1 fixes to be compatible

db/migrations/2018_10_01_000000_create_users_tables.php

docker/Dockerfile

docker/dev/Dockerfile

includes/sys_form.php

includes/view/AngelTypes_view.php

includes/view/Rooms_view.php

includes/view/ShiftTypes_view.php

includes/view/Shifts_view.php

src/Helpers/ConfigureEnvironmentServiceProvider.php

src/Http/SessionHandlers/AbstractHandler.php

src/Http/SessionHandlers/DatabaseHandler.php

src/Logger/Logger.php

src/Middleware/ErrorHandler.php

src/Middleware/SendResponseHandler.php

src/Models/EventConfig.php

tests/Unit/Models/EventConfigTest.php