pin inputs into iso live registry

[blaggacao]

Would your feature fix an existing issue?

With #168 , devos live iso gains the ability to enter the devos devshell and install through it on the target machine during bootstrapping.

Still, the target machine is fetching all inputs again.

Describe the solution you'd like

By pinning inputs into the registry:

• the target will probably use them (if lockfile is not present and declares a different sha)
• more importantly, the nix store closures will get copied over (I hope I'm right?) and therefore there is no deed to fetch those files

Describe alternatives you've considered

n/a

Additional context

• Suggested by @Pacman99 [Merged by Bors] - lib/devos: bake devos repo into live cd #168 (comment)
• similarily, we might want to find a way to copy the devshell closure to the iso, so that entering the devshell uses the baked in nix store closure.

[Pacman99]

Updated code(realized I wrote it wrong):

nix.registry = mapAttrs (n: v: { flake = ${v}; }) (removeAttrs inputs [ "self" "pkgs" "lib" ]);

[Pacman99]

I would say just wait for that PR to get merged

[Pacman99]

I just think all those things - self, inputs, and hosts - are all pretty related and it makes sense to consolidate them into one PR. The hosts part was already approved so its not much of a blocker. And its really an extension of passing self.