Add job for signing the sideload APPX packages
Add a separate job for signing the sideload APPX packages created by the Craft Windows MSVC job.
The job may later be folded into the Craft Windows job, but for beta testing it's easier to have a separate job that can be triggered independently of the time consuming Craft Windows MSVC job.
Should be merged together with ci-notary-service!28 (merged)