phabricator: add
addadded function
This is the most complicated part of the new code, and is responsible for
adding all added files, whether brand new, copied, or moved. This also
includes creating the phabchanges for the original files that have been moved
or copied from, since they might need their awayPaths and type updating if
multiple copies are involved.
Differential Revision: https://phab.mercurial-scm.org/D7050