Update Support diviner document

Summary: This updates the support document, specifically, scopes down feature requests, updates community links, and other wordsmithing. Unsure where to direct bug reports right now, but we'll have something soon?

Test Plan: Read carefully

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Luke081515.2, Korvin

Differential Revision: https://secure.phabricator.com/D18218