Add uploader's Account.Id and upload timestamp to PatchSet

This is the user that put the PatchSet into the change, and
the date and time it was received in by Gerrit.  We track
all of this data in Gerrit1 so we might as well continue to
do so in Gerrit2.

Signed-off-by: Shawn O. Pearce <sop@google.com>
4 files changed