Finalize HTTP API

[FRosner]

Questions

Avoid Duplicate Instances and Templates

• Should /instances return a dictionary instead of a list to not allow duplicate instance IDs?
• Should /templates return a dictionary instead of a list to not allow duplicate template IDs?

The problem is that in JSON there are no maps. There are only objects. And objects have strict rules which keys are valid. These rules do not correspond with Nomads rules for job names so you cannot simply return a JSON map.