CI/CD: Official Docker image on Dockerhub Registry

## Summary
Would be great to have a:
- An official Docker Image for Bitgesell officially available at https://hub.docker.com/ registry for use in environments where continerization is ideal.

Start by reviewing the repository's current build and CI configuration to determine how Bitgesell can be packaged as a Docker image. Define the image's build process, supported usage, and Docker Hub publication steps; done means an official image is available on the Docker Hub registry.

Written by the indexing model from the issue text.