New upload target for VMWare, similar to the ones for AWS and Azure,
allowing users to set credentials for their vSphere instance.
Commit also includes function that performs the actual upload.
- inside RunJob() there is a deferred function which will remove
the entire temporary directory in which images are created, including
the streamOptimized file
- inside testBootUsingVMware(), which wants to use this function,
there is already a deferred function which removes the converted
image
