Fix nsg creation issues

[Mike Barry (jabbera)]

Per: https://docs.microsoft.com/en-us/azure/sql-database/sql-database-managed-instance-connectivity-architecture.

Ensure there is only one inbound rule for ports 9000, 9003, 1438, 1440, 1452 and one outbound rule for ports 80, 443, 12000. Managed Instance provisioning through Azure Resource Manager deployments will fail if inbound and outbound rules are configured separately for each port. If these ports are in separate rules, the deployment will fail with error code VnetSubnetConflictWithIntendedPolicy

This PR fixes this issue, as well as an issue if the NSG does not exist, it would be created empty.

This resolves: #516 and https://github.com/MicrosoftDocs/azure-docs/issues/25509