API changes from v2

* Remove /callback/device, /callback/device/name/{name} endpoints
* Change /device/name/{name}/{command} ds-pushevent and ds-returnevent parameter values to true/false
* Remove /callback/profile endpoints
* Remove /callback/watcher endpoints
* Remove /callback/service endpoints
* Remove /validate/device endpoints
* Rename path on SecretRequest to secretName
* Rename the NewDeviceRequest to DeviceValidationRequest, and add "tags" and "properties" fields into the schema of DeviceValidationRequest