Add scripts to run VMTests and convert images

run_vmtests will run the VMTests after build_image
convert_image will convert the image to VMDK or VHD
make_ova will create a ova image based on VMDK

BUG=b/173643442, b/171738548
TEST=manually test
RELEASE_NOTE=None

Change-Id: I99865424dcaefd1d588f3df7009d70cf86f71c95
Reviewed-on: https://cos-review.googlesource.com/c/third_party/platform/crosutils/+/10662
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
Reviewed-by: Varsha Teratipally <teratipally@google.com>
Tested-by: Roy Yang <royyang@google.com>
Reviewed-on: https://cos-review.googlesource.com/c/cos/scripts/+/59754
Reviewed-by: Oleksandr Tymoshenko <ovt@google.com>
Tested-by: Oleksandr Tymoshenko <ovt@google.com>