Forecast Quantiles Plots can be improved

[antoinecarme]

By looking at this jupyter notebook (large horizon models), in some forecast quantiles plots, the histograms are not visible at all

https://github.com/antoinecarme/pyaf/blob/3b6499491fd1ea2b237e5dae316591dfbde6af45/notebooks_sandbox/large_horizon/long_term_yosemite_tests.ipynb

[antoinecarme]

Proposed improvements :

1. Better separate histograms (original issue solution). Assign a fixed height to each histogram.
2. Use a more meaningful color map (gradient, Blue = Low, Green = Normal, Red = High) for synchronized histograms.
3. Remove some unnecessary borders and yticks.

[antoinecarme]

Previous forecast quantiles plot (Ozone dataset)

New forecast quantiles plot (Ozone dataset)

[antoinecarme]

New forecast quantile plot for large horizon model (H = 512) from the jupyter notebook

[antoinecarme]

Further investigation shows that it is better to use the pre-defined matplotlib color map named 'turbo'.

This color map is the closest to the requested behavior and which has a more continuous color structure,

[antoinecarme]

CLOSED.

[antoinecarme]

Add a final touch for reducing unnecessary colors. Perform a quantization on 'turbo' color map.