New Base Images: Update to Debian 12 "bookworm"

The base images Base, Nginx and PHP are new also available with the tag foxtrott, based on Debian 12. Developer can now change and test their application. Important! The name of the PHP repo changed from "PHP7" to just "PHP". The reason is obviously. Debian 12 comes with PHP 8.2 and not any more with PHP 7.4. The new container domain for PHP is then: eu.gcr.io/vseth-public/php:foxtrott.