lib: updatehub: Add UpdateHub.io support

UpdateHub is an enterprise-grade solution which makes simple to
remotely update all your embedded devices in the field. It
handles all aspects related to sending Firmware Over-the-Air(FOTA)
updates with maximum security and efficiency, while you focus in
adding value to your product.

Signed-off-by: Christian Tavares <christian.tavares@ossystems.com.br>
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>