Change controller to accept new format from iHat
Remove IHatJob model
Conform requests to match changes to iHat API endpoint
Temporarily remove access checks from iHat given that this will be rewritten in the next card.
Extract iHat job parameters into service class to prepare for encrypted messaging.
Add verifier class for encryption/decrypting
Support decrypting data coming back from ihat
Encrypt metadata payload to iHat
HOUND!
Update message_verifier call

- by default, `Rails.application.message_verifier` already uses the Rails secret token.  The argument being passed is an additional salt on top of this.
Merge pull request #697 from Tahi-project/ihat-callbacks

Ihat callbacks