Feature request: support for `nixos-firewall-tool`

[rafaScalet]

Firstly, thanks for the amazing tool — I really like nh and it helps me every day.

I'd like to suggest adding integration with nixos-firewall-tools, for example via commands like nh firewall or nh os firewall.

The main reason is that I use nh as a replacement for most of the "legacy" NixOS commands, such as nixos-rebuild, nixos-build-vms, and others. It fits very well into my workflow.

However, when I need to manage the firewall imperatively (for example, to open a port temporarily and close it later), I still have to use nixos-firewall-tools, which breaks the workflow a bit.

Most of the time, when I need to manage the firewall, this happens:

• I type nh out of muscle memory
• Then I delete it and type the correct command
• After pressing enter, I realize I need to rerun it with sudo

With nh, this is already handled automatically, so having firewall support there would be really convenient.

Related to this, integrating nixos-options could also be very useful, for example via something like nh options or nh os options, so we don't have to specify the flake for the nixos-options command.

Let me know what you think — I'd be happy to help if needed. I'm not a rust developer, but I know a bit of the ecosystem.

[faukah]

Adding this — and replacements of other similar tools — would certainly be interesting, but is definitely not on the roadmap in the near future.

As to why: The current codebase is big and kind of messy, me and @NotAShelf are planning a considerable refactoring, before which adding new shiny features does not make too much sense.

The implementation itself is pretty trivial though, so this could definitely be one of the first things to add to nh if/when we bring more tools into the codebase.