Description:
Add a RollbackToTargetVersion app policy to allow enterprise administrators to enable rollback in conjunction with the existing TargetVersionPrefix policy.

Use case:
The RollbackToTargetVersion Policy meant as a temporary measure when Enterprise Administrators need to downgrade for business reasons. (eg. some business critical application broke)

Existing workarounds:
Many enterprise customers manually uninstall a new version and then reinstall the old version which results in a very tedious and error-prone process.