Define guidelines for base image structure/style

We currently don't have any guidelines on how we want the base Invenio Docker images to be built. Some examples of things that need to be defined:

- Python distribution
- Should we use the Python distribution that comes with the base image? E.g. `python:3.13` or `python:3.13-alpine`?
- Should we install a specific "standalone" Python version using...
- ...the distro's package manager (`yum`, `apt`, ...)?
- ...`uv python install ...`?
- Node.js distribution
- Same as above
- How should we install other dev dependencies like `libxml`, `libpng`, etc.?
- Should we already try to optimize for image size using multi-stage builds, or is this something that "downstream" consumers ensure for their application images?