move the graph generating code over to facets

Bring histogram facets (currently hard coded to 1h buckets) into
the FacetSet module for "timestamp" keys from elastic search. This
then enables us to gut a bunch of code from graph.py and do all
the calculations with facet counts instead.

At the same time, make all the graphs run for a full 2 weeks of
data, so they are comparible to each other visually (the sliding
window start time was less useful in seeing how the graphs
compared)

Change-Id: I971d52b5de514d0607bd8217837aed3895472d05
sort the graph list by number of fails

this sorts the graph list by the number of fails found during the
time period. That will naturally make the worst issues float to
the top.

Ensure our time span is a full 14 days.

Change-Id: Ic26e7b2196b80fae969a768289e0550a46de8579
set y axis on failure rate graph

instead of letting the yaxis drift based on whatever data we've
gotten make it a fixed range from 0 - 100 (as it is percentage).
This makes it easier to see visually when things are good or
bad on a given day.

Change-Id: Ia136ab26c9b4149d3e0cb5b1b17baa145a7a1c32
Merge "move the graph generating code over to facets"
Merge "sort the graph list by number of fails"
Merge "set y axis on failure rate graph"