crowbar: init at unstable-2020-04-23

[Pamplemousse]

Motivation for this change

Bring crowbar to nixpkgs as part of #81418 .

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 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.

[Pamplemousse]

As per @jonringer recommendation, I PRed galkan/crowbar#45 to make the package pip installable.
Waiting for their feedback / merge.

[jonringer]

if you want, you can include your PR as a patch, and "re-package" this :). I think that would be acceptable

[Pamplemousse]

@jonringer I am not too sure about what you meant by your comment...

As the PR to upstream has been merged, I updated the one here to unstable-2020-04-23 referencing the latest commit.
However, the "sanity check" triggers a

Traceback (most recent call last):
  File "/nix/store/s2jzaarx2gwbiqgpcxbl7znibafjfrag-crowbar-unstable-2020-04-23/bin/.crowbar-wrapped", line 6, in <module>
    from crowbar import main
ModuleNotFoundError: No module named 'crowbar'

That I can't reproduce. Did I package crowbar wrong?

[jonringer]

LGTM
shows usage

https://github.com/NixOS/nixpkgs/pull/85797
1 package built:
crowbar