Create deterministic images for CTA services

At the moment we build a generic base image in our CI that has the CTA RPMs available, but not installed. This is problematic if we ever want to use these images in a (pre-)production situation

For anything outside of CI, it is important that these images are deterministic and slim(ish). That is, everything comes pre-installed (not installs at runtime!) and no redundant dependencies are included.

I will be adding these deterministic images. This means:

• Create a separate Dockerfile for each service that is deterministic
• Make them a manual (but optional) job in the CI. They won't replace the generic CI images for now

The main motivation for this will be the gRPC frontend: if we have a deterministic image, it will be very easy to test this in preproduction.