Regularly build samba image

[andrin55]

In light of the recent samba security issues, it would be great if the container is automatically built in regular intervals (for example once every week).

This would be great to quickly fix security issues and bugs arising in samba, since it is already fixed in the current alpine package version.

[instantlinux]

To implement this safely, the test pipeline will need functional testing with enough coverage to look for breaking-changes of commands used by the entrypoint script here. There would also need to be a polling script to look for new versions, and then to update Dockerfile and helm Chart.yaml.