[feature] Add support for DataDog's malicious software package dataset

[funnelfiasco]

Is your feature request related to a problem? Please describe.

Malicious packages exist in public repos, and sometimes people bring them in.

Describe the solution you'd like

Parse the DataDog Malicious Packages Dataset to pull in known-malicious packages and flag them when they appear in the graph.

Currently, the dataset provides JSON manifests for known malicious PyPI and NPM.

I'm thinking this would be a certifier that runs and creates a CertifyBad node for packages.

[robert-cronin]

I can work on this one, if it hasn't been started on yet. @funnelfiasco could you please assign me?