Add support for AWS Elastic Fabric Adapter

[christopheredsall]

[james-grant1]

Checklist

Setup

• Create ENI for EFA
• Create Placement group for compute nodes

For compute nodes

• Select EFA ready instances
• Enable EFA on nodes
• Add instances to placement group
• Attach to EFI

[james-grant1]

AWS docs for placement groups (this work will need a cluster group):

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/placement-groups.html

[james-grant1]

AWS docs for EFA:

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/efa.html