Return binary flag when with filediffs and allow querying by the binary flag.

Review Request #10729 — Created Sept. 26, 2019 and updated — Latest diff uploaded


Review Board


RB Tools required getting the binary status of each filediff so it
could determine which files need an accompanying file upload. This
allows RB Tools to query the backend for the filediffs for a diff. The
filediffs returned will contain the binart flag. An optional flag is
also provide for querying only for filediffs that have the binary flag
set to either true or false.

Included unit test for these changes.