Support pet name for cuttlefish instances

Add new argument "--pet-name" for Acloud create. Users can create
cuttlefish instances with pet name.

Bug: 213935001
Test: acloud-dev create --pet-name my-bmw
      acloud-dev create --local-instance --pet-name codelab
Change-Id: I415485b23be550a037c6f3a315485c29a31e8ab3
7 files changed