Blog: Nix in the Wild: DRYing Out Your Codebase with Reusable Library Functions

This merge request is related to this blog post. It introduces library functions for creating both Python and Flink projects. I’ve also added simple checks to ensure everything works as expected. Since the initial Flink jobs were mostly placeholders with a 50/50 chance of running in their original state, I refactored them to make them functional. However, please note that these refactoring changes are not central to the blog post's content; they were only necessary to ensure that Nix can successfully run the code. Additionally, I removed the Docker images from the repository since everything can now be handled directly with Nix.