Add msi template job

This PR adds in the ability to dynamically create an MSI along with the uber_build. The job is kick off as a downstream job to the main packaging job. This is to ensure the git bundle has been generated, and is accessible to us. This also changes the msi job name to use the short sha rather than the full sha because otherwise, the path is too long, and it dies. Did you know the max path allowed on windows is 260 characters? NOW YOU DO!

The order is like so:
packaging => msi => repo => downstream
OR
packaging => repo => downstream

depending on weather or not you have buid_msi set in build_defaults
@melissaanne how about have length be an integer that defaults to 40? Then you can always pass --short, and the code would be `Pkg::Util::Execution.ex("#{GIT} rev-parse --short=#{length} HEAD").strip`. For the short sha, pass 7.