Improve nomad deployment resilience
Improve nomad deployment resilience

* Configure the healthy threshold and deadline
* Enable auto rollback on failed deploy
* Set the stagger to a more appropriate value for a go app


Former-commit-id: fa8ab1a977de09f5ae5958e8a712e08947990a51
Former-commit-id: d84a91883613555f7be83260103780da827789d2
Former-commit-id: f28b7854685f0dcdb722d9aed7cf3cd7eb44d2d8
ONSdigital/florence,ONSdigital/florence,ONSdigital/florence,ONSdigital/florence