Support gMSA for Azure ATP Reader Account

Please support using a Group Managed Service Account (gMSA) for the Azure ATP reader service account.  Also have the AATP installation default to using a gMSA to help improve security when setting up AATP.

And for customers who already have AATP set up, once this option becomes available, please suggest this in the console so that environments can switch to using a gMSA if/when this becomes available.

Thanks!