[DOCS] Neptune sagemaker instructions

[lmeyerov]

Is your feature request related to a problem? Please describe. A user reports Sagemaker notebook instances cannot seem to use Graphistry, even when a Graphistry server is in the same VPC and its own notebooks can query neptune

Describe the solution you'd like Documented solution linked here + neptune sagemaker

Additional context As a reproduction step, we should confirm against the neptune identity graph demo