Use official Theodolite container images

In our deployment files (e.g. Helm) for the new Kotlin-based implementation, some images are used, which are located in container registries of individual developers.

We need to:

• Identify where such images are used (i.e. is it only Helm?)
• Make all images available at the ghcr.io/cau-se registry (will use theodolite-kotlin tag for now)
• Maybe make all images used by Helm configurable via values as it is the case with most other charts
• Update the release process docs to reflect the fact that image tags need to be changed
• When merging !83 (merged), theodolite-kotlin tags should be changed to latest