Using arithmetic transformers in pipeline

Arithmetic transformers has been just finished in Ceilometer.
That allows us to move very ugly computation of percentage
from TripleO-UI to Ceilometer pipeline, where it belongs.

Adding computation of swap and cpu utilization.

Change-Id: I69fc1b4ebf740e34d24b26eff922b6b40e72c08a
Merge "Using arithmetic transformers in pipeline"