feat(distribution): add Nix Flake based duckdb shared library + jar output

[thenonameguy]

Hey, thanks for the great library!

For ease of use, I added a Nix-based slim jar distribution method for my own purposes.
Would be happy to upstream the change, if you don't think it pollutes the repo too much. ✌️

[cnuernber]

This is great - people like to have the binaries in the jar as it simplifies other things. I'm going to merge this assuming it doesn't break other things such as the existing scripts/deploy pathway. My guess is you will often have to rebuild the lockfile as we aren't currently using nix here.

[thenonameguy]

Thanks for merging! 🙏

There actually exists an automated solution via Github Actions that opens a PR to keep the lockfile in sync:
https://jlesquembre.github.io/clj-nix/github-action/

I'll use the this repo now, instead of my fork.
I'll open a PR next time I upgrade it so the above is set up, without much manual intervention.