[challenge 4] - data export from Iot Central

[lenisha]

current instructions ask to use Iot Central Data Export (Legacy), we have tested it with newer version of Data Export and it worked with following changes:

• setup Data Export
  Add destinattion pointing to IotConnector EventHubs Connection String and export Telemetry:

• update device template in Iot Connector as per https://github.com/microsoft/iomt-fhir/blob/master/docs/Configuration.md#iotcentraljsonpathcontenttemplate

{
    "templateType": "CollectionContent",
    "template": [
        {
            "templateType": "IotCentralJsonPathContent",
            "template": {
                "typeName": "heartrate",
                "typeMatchExpression": "$..[?(@telemetry.HeartRate)]",
                "values": [
                    {
                        "required": "true",
                        "valueExpression": "$.telemetry.HeartRate",
                        "valueName": "hr"
                    }
                ]
            }
        }
    ]
}