Add Neptune Analytics support

[michaelnchin]

Issue #, if available: N/A

Description of changes:

Adding new sample notebooks and compatibility changes in support of the release of the new Neptune Analytics graph database engine .

• Eight new Analytics samples notebooks, installed under 02-Neptune-Analytics.
  • Subsections: Getting Started, Graph Algorithms, Sample Use Cases.
• neptune_service field in %%graph_notebook_config
  • Accepts either “neptune-graph” or “neptune-db” as value. You can use this field to access both P8 and a Neptune DB endpoints from the same notebook.
  • Auto-set to “neptune-graph” if using the CFN template
• Analytics parameters for %%oc
  • --query-timeout
  • --plan-cache [auto|enabled|disabled]
• Batch data loading via %load
  • New parameters: -c/—concurrency, -pc/--periodic-commit
  • %load will be automatically restricted to Batch or Bulk load mode based on neptune_service in config.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.