Rename project -> product on edit/create UIs

Summary: Ref T3092. Ref T3549. Modernize the product creation and edit UIs and make them say "product" instead of "project".

Test Plan:
  - Created products.
  - Edited products.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T3092, T3549

Differential Revision: https://secure.phabricator.com/D8636