Add constants for default options in DiffXWriter.
Review Request #11728 — Created July 17, 2021 and submitted
These default options are used when writing a DiffX file. The options
were previously stored as hard-coded values in function definitions, but
this meant that other parts of the codebase couldn't refer to those
It also adds a new options definition,
MetaFormat, for available
metadata formats. This just includes
Unit tests passed.
Used this with the upcoming DOM change.