Merge master into staging-nixos

##### mixRelease - Frontend dependencies (javascript) {#mix-release-javascript-deps}

For phoenix projects, inside of Nixpkgs you can either use yarn2nix (mkYarnModule) or node2nix. An example with yarn2nix can be found [here](https://github.com/NixOS/nixpkgs/blob/master/pkgs/servers/web-apps/plausible/default.nix#L39). An example with node2nix will follow. To package something outside of nixpkgs, you have alternatives like [npmlock2nix](https://github.com/nix-community/npmlock2nix) or [nix-npm-buildpackage](https://github.com/serokell/nix-npm-buildpackage)

For phoenix projects, inside of Nixpkgs you can either use `fetchYarnDeps` or `buildNpmPackage`. An example with `fetchYarnDeps` can be found [here](https://github.com/NixOS/nixpkgs/blob/master/pkgs/by-name/pl/plausible/package.nix). An example with `fetchYarnDeps` will follow. To package something outside of nixpkgs, you have alternatives like [npmlock2nix](https://github.com/nix-community/npmlock2nix) or [nix-npm-buildpackage](https://github.com/serokell/nix-npm-buildpackage)

##### mixRelease - backend dependencies (mix) {#mix-release-mix-deps}

Each tool has an abstraction to just build the node_modules (dependencies) directory.

You can always use the `stdenv.mkDerivation` with the node_modules to build the package (symlink the node_modules directory and then use the package build command).

The node_modules abstraction can be also used to build some web framework frontends.

For an example of this see how [plausible](https://github.com/NixOS/nixpkgs/blob/master/pkgs/by-name/pl/plausible/package.nix) is built.

Then when building the frontend you can just symlink the node_modules directory.

## Tool-specific instructions {#javascript-tool-specific}

      attr ? ${name} && !(hasPrefix "@" attr.${name})

    ) "Systemd ${group} field `${name}' is not a systemd credential";

  assertRouteMetricOrTriple =

    name: group: attr:

    let

      isMetric = n: 0 <= n && 4294967295 >= n;

      parts = splitString ":" attr.${name};

      partsValid =

        length parts == 3 && all (p: (match "[0-9]+" p) != null && isMetric (toIntBase10 p)) parts;

      valid = (isInt attr.${name} && isMetric attr.${name}) || partsValid;

    in

    optional (attr ? ${name} && !valid) (

      "Systemd ${group} field `${name}' must either be an integer in the range [0,4294967295]"

      + " or a string containing three integers separated with `:`"

    );

  checkUnitConfig =

    group: checks: attrs:

    let

            -i ${channelSources} --quiet --option build-use-substitutes false \

            ${lib.optionalString config.boot.initrd.systemd.enable "--option sandbox false"} # There's an issue with pivot_root

          mkdir -m 0700 -p /root/.nix-defexpr

          ln -s /nix/var/nix/profiles/per-user/root/channels /root/.nix-defexpr/channels

          ln -sfvT /nix/var/nix/profiles/per-user/root/channels /root/.nix-defexpr/channels

          mkdir -m 0755 -p /var/lib/nixos

          touch /var/lib/nixos/did-channel-init

        fi

          assertion = cfg.efiSupport;

          message = "Secure boot is only supported on EFI systems.";

        }

        {

          assertion = !cfg.enableEditor;

          message = "Editor is unconditionally disabled by Limine.";

        }

      ];

      boot.loader.limine.enrollConfig = true;