PHP 8 deprecations in Repositories

[rk-mxp]

The Repositories use the deprecated fetch and fetchColumn functions of doctine.
These throw PHP 8 deprecations because they don't set fetchMode which is defined as int in https://www.php.net/manual/de/class.pdostatement.php

Solution:
Replace fetchColumn with fetchOne and fetch with fetchNumeric(), fetchAssociative() or fetchOne() (whatever is required).