Motivation for this change

Opening this as a source-version of #46062 and to gather feedback on the approach. I'm still fairly novice in writing nix expressions and derivations but @NinjaTrappeur suggested I take over patchwork since I'm familiar with the project as a whole and have built an electron client myself. @samueldr also suggested in this comment that a source version would be preferable.

tale:net is not http://github.com/ssbc/patchwork/ but very similar in architecture and spirit. They are both based on http://scuttlebutt.nz/ and are electron apps. Once I figure out the remaining questions, I can adapt the same recipe for patchwork and patchbay

Also: This depends on #45997 but could be decoupled. I thought it would just be easier to test this with both new packages present.

ps: See #46000 for two standalone tools without electron

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Fits CONTRIBUTING.md.

Question:

• Is the node2nix sub package approach sane?

Previously, I just used this shell.nix to develop. In it, I can run npm i && npm run build (which is an alias for node .electron-vue/build.js && electron-builder) and run dev to make builts and development versions.

I discussed with @NinjaTrappeur that this invovles fetching a pre-built electron version from npmjs.com. I'd rather not do this.

In principle it is enough to run node .electron-vue/build.js && cd ./dist/electron && electron . and this can work on archlinux, when all the node and electron ABI versions correctly line up.

I'm having trouble understanding how to do the npm i && node .electron-vue/build.js with node2nix, though. I generated the env from the source package.json and made some changes to it so that it doesn't import nixpkgs twice. The output looks fine but I'm not sure yet how to copy node_modules into this out/ or if I should run the node .electron-vue/build.js in the embedded node env.

• re systrayhelper: init at 0.0.3 #45997: is propagateBuildInputs the correct method to have this package as a runtime-dependency to talenet or should add something to the fixupPhase of the node-env?