Support inferentia instances

[deliahu]

Description

• https://aws.amazon.com/ec2/instance-types/inf1/
• inferentia blog post, announcement

[RobertLucian]

@deliahu letting you know I'm going back to this ticket (as we have previously discussed). Been busy with #948 so far. Hope that's okay with you.

[RobertLucian]

Useful resources:

• https://github.com/aws/aws-neuron-sdk/blob/master/docs/neuron-container-tools/tutorial-k8s.md - device plugin to expose inf chips to k8s.
• https://github.com/aws/aws-neuron-sdk/blob/master/FAQ.md - faq on aws neuron sdk.
• https://aws.amazon.com/blogs/machine-learning/reduce-inference-costs-on-amazon-ec2-for-pytorch-models-with-amazon-elastic-inference/ - for pytorch stuff.