Code of Conduct, mk II

* does not include contribution policy and governance documents
* explicitly defines harrassment
* explicitly defines consequences
* adds grievance policy
* introduces notion of specific points of contact for abuse reports; still need a list of actual names to go into the policy
* adds credit and link to the npm, Inc. Code of Conduct
* incorporates community feedback
I love this entire section: positive suggestions have a lot of power to shape as well.