Fixes: #54

The objective is to upgrade from the alpine 2.17 base image to an official DockerHub Python 3.10 base image. We opted for a Debian 12 (bookworm slim) base image.

No alterations have been made to the current CKAN 2.9 builds.

Efforts were made to streamline the system libraries to only include essential components.

Upon successful testing and integration of this PR, several improvements will be realized:

• Implementation of Multi-Stage Builds, assuming it reduces image size and increases image security
• Optimization of Docker Layers and subsequent caching mechanisms
• Enhancements to render the base image more suitable for production environments
• Assess the feasibility of substituting Supervisor with a native Docker Compose (or Docker) approach for managing CKAN process restarts.
• Fix: Running "ckan -c ckan.ini db upgrade" on master fails #60

I'm happy to take suggestions for better naming of files and images