PHPStan was released with first stable public version 1.x.
The version is updated together with extensions.
The new version finds new issues which are solved right away to not
break CI.
Pages can not be copied by administrators as DataHandler will copy all
pages, including tx_tracking_* tables.
Those are not allowed on tables which will result in error messages.
A test is added to simulate the action and ensure it doesn't fail with
errors.
Results: #52
