Extend actions by referring to an image

[theBadT]

The state of the art approach of actions seems to be, providing the image property within the action, in case special environment is required.
Hence we need to:

1. add the image to every single action currently present
2. refer to the dockerfile of the image, instead of a built image

see https://docs.github.com/en/actions/sharing-automations/creating-actions/creating-a-docker-container-action#creating-an-action-metadata-file

Check in how far building the image just in time affects pipeline performance