Add subnetIds in Container group Instances instead of network profile id

[arjaiswa]

Is your feature request related to a problem? Please describe.
Currently creating Azure container Instances with Network profile Id is causing the throttle issue with network calls. and ACI team is suggesting creating using Subnet Id as per the new Rest API :

Reference Link: https://docs.microsoft.com/en-us/rest/api/container-instances/container-groups/create-or-update#containergroupsubnetid

Describe the solution you'd like
Please add Subnet Id in Container Group creation.

[weidongxu-microsoft]

This SDK is in maintenance, and will not support new feature.

Please plan for migration to https://aka.ms/azsdk/dotnet/mgmt