Package as a Nix flake to fix problems with dependencies

[numinit]

I noticed some complaining in the README about dependency issues... so I solved the problem. :-)

Enjoy.

[sandreas]

Phew, I always wanted to try nix :-) Well, It may take some weeks until I can integrate this PR, I'm on vacation right now and promised everyone not to be too much into my projects ;)

But thank you very much for providing this, I really appreciate it.

[numinit]

No worries, the project was extremely well suited for doing this. Multiple dependencies with the need to bundle them without something like Docker. Still need Nix, but at least the derivations can be packaged to other things like Docker...

[sandreas]

@numinit Thanks for your sponsorship. As I said, ATM I'm on vacation, but as soon as I'm back, I'm gonna prioritize issues and put your name (and if you wish your logo) into the project readme.

In the next weeks I plan to publish a sponsors overview on my homepage (https://pilabor.com) with more details about the projects I plan to support. Probably the following projects will be on the list and a survey will be published, because they are the most valuable and transparent projects with charitable purpose available in Germany (where I live):

• WWF (https://www.wwf.de/ - German, https://www.worldwildlife.org/ - International)
• Welthungerhilfe (https://www.welthungerhilfe.org/about-us)
• Ärzte ohne Grenzen (https://www.aerzte-ohne-grenzen.de/work-with-us)

Since charitable donations are only useful if a certain amount is donated (at least 150$), I have to wait until the sponsorships pass this value, but I publish the donation receipt, as soon as it's done.

Thank you for all your support.