Using a batch pool subnet with service endpoints to avoid load balancer charges

1. Inside the CoA vnet, create a subnet named batchsubnet with service endpoints for Storage, SQL, and ACR.

2. Run the deployer with --Update and --BatchNodesSubnetId "/subscriptions/${SUBSCRIPTION_ID}/resourceGroups/${RESOURCE_GROUP_NAME}/providers/Microsoft.Network/virtualNetworks/${COA_VNET_NAME}/subnets/batchsubnet"