simplify build process using nix

[disassembler]

Makes it easier to use for users that don't have docker installed.

Example Usage:

mkdir -p ~/.local/share/daedalus-turbo/data
nix run .# -- sync-http ~/.local/share/daedalus-turbo/data

[sierkov]

@disassembler, thank you for the PR! That's a valid point. The repository is currently in a proof-of-concept stage, so speed of development and, thus, speed of testing are important, and having one build path makes release testing quicker. Will definitely consider Nix support for the beta stage.

P.S. I'm a very occasional user of Nix myself, so If you could share some relevant links to articles/documentation with best practices for supporting and testing Nix builds for multiple platforms (in the beta stage, the project will target Linux, Mac OS, and Windows), that'd be much appreciated!

[disassembler]

We have our own infrastructure so have a rather complicated setup, but for a simple case like this, I'd look into nixbuild.net with GHAs. https://github.com/nixbuild/nixbuild-action

I'd suggest just merging this. Just having a flake.nix even if it isn't perfectly maintained makes it a lot easier for a nix user to modify if it breaks. Otherwise there's s lot of rebasing and cherry picking on top of this commit every time.