scripts: Setup storage for moblab vm

This CL adds a '--moblab' option to cros_start_vm for
starting an image with a moblab environment.

The moblab environment provides:
  - A 35GB disk for use by the VM
  - 4GB of allotted RAM
  - SSH from host to guest still works, you will need to
    follow the SSH instructions for moblab
    (ie. testing keys and ssh config)
  - Hostforwarding access of moblab webpages:
    - 127.0.0.1:9991 leads to the Mob* Monitor on the vm
    - 127.0.0.1:8888 leads to the AFE on the vm
  - Ethernet over USB connections from the vm to a DUT
    work. You need to specify the correct USB device for
    passthrough.

BUG=chromium:532548
TEST=Launched the VM and checked that storage was present,
checked that ssh worked and that I was able to access the
AFE and Mob* Monitor pages from the host.

Change-Id: I4a5d04475fb756f87f22ca8b1c541d501d6d934a
Reviewed-on: https://chromium-review.googlesource.com/303499
Commit-Ready: Matthew Sartori <msartori@chromium.org>
Tested-by: Matthew Sartori <msartori@chromium.org>
Reviewed-by: Simran Basi <sbasi@chromium.org>
2 files changed