Add template guide & minor cleanup

[Kostis-S-Z]

What's changing

Clean up of the template repo to make it easier to onboard developers and provide a better experience when they use the template to build their Blueprint.

Specifically:

• Add guide on how to use and adapt this repo to the dev's needs
• Standarize the term blueprint-template across the repo so its easy to find-and-replace with the project name of your choice (see template_guide.md for a detailed explanation).
• Add explicit note on installing pre-commit when doing development work on a blueprint
• Add note for contributors in README referencing the template guide
• Remove package.yaml: GH workflow to build docker image that pushes it to the MZAI docker hub
• Remove default dependency loguru.

How to test it

[N/A]

Additional notes for reviewers

Please think of any other ways we can make this even better!

[alexmeckes]

I think this looks good