Generate the nix declarations by querying packages.edgedb.com

[aljazerzen]

Currently there is only a few edgedb-server versions declared in the flake.nix.

Ideally, we'd be able to use the source-of-truth for edgedb releases, packages.edgedb.com, to generate all available version derivations.

I'm not experienced enough with nix to do this in pure nix, so I'll probably fallback to using Python to do this. Does anyone have more experience?

[aljazerzen]

This is now mostly solved by 8f79363

What remains is to make it truly automatic, so one can run a single command and have it be done without copy-pasting.

[darinkishore]

Could you see if the PR above PR does what you'd like it to? @aljazerzen