https://github.com/nix-community/NUR is a Nix community project that
aims to make out of tree derivations more easily discoverable and
accessible to Nix users. Converting the nix-bitcoin repo to conform to
that style is a minor change and enhances reusability of its
components. For instance, I could slap on the clightning module more
easily onto my existing bitcoin node without having to redeploy the
whole as nixops driven installation. Having the repo in NUR style
would make that easier.
The strategy of invoking node2nix inside a derivation (installPhase in
this case) does not work, as under NixOS installations there is no
network traffic allowed during a derivation build. Hence, we move
node2nix outside and rewrite the packaging into the modules.
Also switch to callPackage instead of plain imports. This could
probably be done on all other imported packages inside of
nix-bitcoin-pkgs.nix.
