Adds replaceEntity and insertOrReplaceEntity
Adds replaceEntity and insertOrReplaceEntity

I recently used your Table Storage service and I could not find any reference in your documentation on how to update/edit an existing entries.
This is why I propose to add under the Table Storage section:
- an example of **replaceEntity**
- 2 mentioning of **insertOrReplaceEntity**
Azure/azure-storage-node,XiaoningLiu/azure-storage-node,XiaoningLiu/azure-storage-node,Azure/azure-storage-node