Use shared Task definitions

[Diaphteiros]

Note that this PR changes the artifact paths from ghcr.io/openmcp-project/github.com/openmcp-project/... to ghcr.io/openmcp-project/....

[cla-assistant]

All committers have signed the CLA.

[cla-assistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}