This endpoint will return all the dimension names for a given metric
name.
Added dimension-names for influx in python api and java api
Added dimension-names for vertica in java api
Depends-On: Id981dafd00778a6d4a376b9ceab011231e94c0c6
Change-Id: I0192ccb9276ea94103a477bd2ad7d10f21e64d31
Implements: blueprint dimensions-api