Improve naming of entry-related Less variables and move to defs.less.

Review Request #9175 — Created Sept. 6, 2017 and submitted — Latest diff uploaded

Information

Review Board
release-3.0.x
c1702d9...

Reviewers

This moves the entry-related variables out of reviews.less and into
defs.less, renaming them in the process in order to have a more
consistent naming scheme and to make these available to extensions that
may want to reference them. No actual styling has changed.

Tested that the entries still render correctly.