P1 Update English articles for Fx 4

P1 Contributor Documentation Update

Audit and inventory all existing contributor documentation [October 15]
- Decide what should be combined, deleted and updated. We'll work with Matthew and Cheng to do this for the Live Chat and Forum docs.
- Create a timeline for updating the docs
Complete drafts of new docs [Mid November - in time for the KB sprint]
Finalize docs [End of November]