adding workloadType property for Baremetal scenarios (#14101)

Author: bhbhise

specification/network/resource-manager/Microsoft.Network/stable/2021-02-01/networkInterface.json

@@ -1160,6 +1160,10 @@
           "readOnly": true,
           "$ref": "./network.json#/definitions/ProvisioningState",
           "description": "The provisioning state of the network interface resource."
+        },
+        "workloadType": {
+          "type": "string",
+          "description": "WorkloadType of the NetworkInterface for BareMetal resources"
         }
       },
       "description": "NetworkInterface properties."