Code of Conduct, mk II

Changes from the original:

* does not include contribution policy and governance documents
* explicitly defines the scope of the Node.js Project
* 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

Please limit discussion on this issue to the Code of Conduct itself:
  * ambiguous or confusing wording
  * typos
  * contradictions
  * scope of the document

Discussion of the necessity or relevance of a Code of Conduct for the Node.js Project is irrelevant to this PR, and should be conducted elsewhere.
No, of course that's not what I'm suggesting. I'm suggesting that a CoC scoped so broadly as to include any conflict where one participant is a member of the vaguely-defined "Node.js community," regardless of the relevancy of that conflict **to the Node.js project,** is counterproductive. There are presumably more-appropriate forums to mediate disagreements entirely unrelated to Node.js.

My suggestion that I might report Adria for harassment wasn't sarcasm, it was satire. That said, as someone who has been victimized with false accusations of harassment, I am being entirely serious when I say that the lack of adequate provisions to safeguard against false accusations in this CoC makes me feel quite unsafe.