User asked for two lines instead of side-by-side bars at monthly
granularity. Converts panel 25 from barchart to timeseries:
* type: barchart -> timeseries
* format: table -> time_series, SELECT month::timestamp AS time
* drawStyle line, lineWidth 2, fillOpacity 0, showPoints auto
* Same blue (contributions) / green (market gain) colour overrides
Where the green line rises above the blue line is the visual cue that
the market out-earned new contributions for that month -- the trend
the user wants to track.
Diff is small (15 ins / 28 del) because the bar-chart-only fields
(barRadius, barWidth, groupWidth, stacking, xField, xTickLabelRotation)
are dropped.
e110b40a4a