Add handling for a vendor target that will handle specific vendor
requirements from a package's options.conf.
The initial change adds handling for 'cargo vendor', creating a new
repo in the configured git repositiory and setting up the ARCHIVES
variable in the package's Makefile.
If the repo already exists, the tooling will check if a repo change
was detected after re-vendoring the sources. If a change is detected
the new content will be pushed and the ARCHIVES variable will be
updated.
Signed-off-by: William Douglas <william.douglas@intel.com>
