Re enable node monitoring

In the past, it was possible to see node metrics in BatchExplorer through Application insights together with [batch-insights](https://github.com/Azure/batch-insights).

Since this is deprecated and *not working* any more, the only way to get node monitoring is to use [batch accounts in user subscription pool allocation mode and look for metrics in portal.azure.com](https://techcommunity.microsoft.com/blog/azurepaasblog/integrating-azure-monitor-in-azure-batch-to-monitor-batch-pool-nodes-performance/4428929).

It would be very welcome if we could monitor our pool nodes in BatchExplorer like it was in the past.

See also: https://github.com/Azure/Batch/issues/187