Motivation for this change

Update imv to version 4.0.1. Changelog: https://github.com/eXeC64/imv/blob/a6deca0ad390d29ada6d72584a1be835a3913139/CHANGELOG#L4-L40

I kept the standard imv build, that produces both x11 and wayland versions. We could also separate imv or/and add flags to enable which version is actually build to keep the dependency smaller. Given however that the closure size decreased from ~140M to 123M I think it's okay for now as it is.

Also separated the stuff needed to build the manpage into nativeBuildInputs

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 nix-review --run "nix-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)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

Notify maintainers

cc @rnhmjoj