Dashboard color standards and better aggregations.

The Grafana Dashboard has been updated enforcing a color standard. Now
all the graphics related to mutated request are purple, accepted
requests are green, reject requests are red.

Furthermore, some queries have been updated to aggregate different
time series in one single line.  This is necessary because we have
many label in the metrics and each different value generate another
time series. Thus, we can leave with many lines in the graph which
does not tell use useful info.

Author: jvanz