Missing validation on 'type', when creating a new Iot-device

[ellesgaard]

Server returns 500 when creating an IoT-device without a type.
Response should be 400, with a validation error of missing/incorrect type.
As is done, if name is missing.

Submitting w/o a type returns 500

Submitting w/o a name returns 400

Check that server returns 201, when all three params is present

[ramogens-OS2]

Thank you for pitching in and for thorough reporting @ellesgaard . We'll put the bug in the maintenance backlog.