Remove neuron-rtd sidecar in favour of KMD (Neuron kernel mode driver)

[RobertLucian]

Description

As of release 1.9.0 of the aws-neuron SDK, it is now possible to get rid of the neuron runtime sidecar and instead just resort to the Neuron KMD to ensure all communication with the accelerator.

Additional context

Documentation on the neuron runtime and KMD:
https://github.com/aws/aws-neuron-sdk/tree/master/docs/neuron-runtime