Add a general comments feature class

Review Request #8471 — Created Oct. 17, 2016 and submitted — Latest diff uploaded

Information

Review Board
release-3.0.x

Reviewers

The new general comments feature can be enabled or disabled with the
reviews.general_comments feature. Disabling this feature will disable
all UI elements for it, as well as the web API resources for it.

Tested with reviews.general_comments enabled and disabled. When
disabled, general comments cannot be created and the UI elements do not
appear.