Motivation for this change

These packages are currently failing to build because because they rely out outdated dependencies. But when you look at upstream, it looks like they're hopelessly outdated.

1. https://github.com/Paperspace/gradient-sdk redirects to https://github.com/Paperspace/gradient-utils (project name changed).
2. https://github.com/paperspace/paperspace-python has been archived on github, and they've apparently moved to https://github.com/Paperspace/gradient-cli.
3. I tried for a hot second packing the new versions, and they're a bit of a mess too. They also hardcode strict dependencies on outdated versions of packages like attrs<=19. That might be a project for someone else.

Our paperspace package looks like it hasn't been updated since 2018-06-10, has no tests, and aparently is supposed to interact with a cloud service. So it's pretty unlikely it works anyways. I propose to mark them as broken, or perhaps just remove them.

cc maintainers @thoughtpolice @freezeboy.

Things done

• 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.