message: Update bigDataPool.json, add XXXLarge to NodeSize enum
  * Update bigDataPool.json, add XXXLarge to NodeSize
  Update 'bigDataPool.json', add `XXXLarge`  value to `NodeSize` enum list
  * Fix grammar error
diff: "Medium",
  "Large",
  "XLarge",
  - "XXLarge"
  + "XXLarge",
  + "XXXLarge"
  ],
  "type": "string",
  "description": "The level of compute power that each node in the Big Data pool has.",
  