PR to handle vm images for create vm scenarios

Changes in the PR include
1. Support for creating virtual machine using vm images.
2. Support for creating docker vm using vm images.
3. Image Show & Delete Image would now delete vm images.
4. Support for A8,A9 role size for create vm.
Can you make the requiredEnvironment change in all of the tests owned by MSOpenTech? This is a very important change and helps the user running the tests to set the required environment variables instead of guessing what needs to be set.