[Chore] add health check endpoint

[nodox]

We want a way to moniter cronut in Pingdom. Thus a health check endpoint is created to allow the service to see if our clock work job has fired.

[werkshy]

This is neat, I like the approach of storing the clock run in the DB and checking the DB for it - two birds, one stone.

[nodox]

You can thank @pjambet for the idea!