(CPR-59) Move git utilities into library

This commit goes through and takes all of the git based utilities in
00_utils.rake and moves them to their own ruby file in packaging. It
also goes through and finds every use of the old version and replaces it
with the new one. Finally it deprecates the old one so as to show a
warning message in the event the old one is still used. However it won't
break, just warn.
Even in that case, we never use the tar parameter for anything other than tar currently. So it doesn't seem like a large issue. The tar constant could be smart and try to find gtar on solaris/aix/osx if available. I also don't think the constant idea needs to happen in this pull request.