Backports the create-spdx classes from the latest versions on master.
This backport is a simple copy with no modifications, as its too
complex to cherry-pick all the corresponding changes. This will give an
appropriate base commit for subsequent changes and if necessary
additional backport cherry-picks from master in the future.
Signed-off-by: Joshua Watt <JPEWhacker@gmail.com> Signed-off-by: Steve Sakoman <steve@sakoman.com>