Allow AMI and Security Group selection (in combination with PR on Autolab)

[jhs-panda]

• Retrieves available AMIs and existing security groups on Tango side and passes to Autolab for user to select.
• Whenever a job is added to Tango, the currently requested AMI and security groups are passed along
  • used for VM if not default
  • otherwise, just the existing default on Tango side (thus should not break anything, just give users options)