prometheus-cups-exporter: This shouldn't be packaged

[ThoreKr]

This exporter is outdated, broken by design and simply shouldn't be packaged.

Motivation for this change

There is no point in having this garbage version as a package. For peace of mind I want it gone.

Things done

Deleted the according .nix file created in #67634

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• 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 nixpkgs-review --run "nixpkgs-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.

[cole-h]

Some comments:

1. You need to remove it from pkgs/top-level/all-packages.nix.
2. You should add an alias to pkgs/top-level/aliases.nix stating why it was removed.
3. If it were me, I'd reword the commit to be prometheus-cups-exporter: remove or ...: drop.

[ThoreKr]

@cole-h Thanks for the remarks, I fixed these points.

[cole-h]

Perfect, thank you!