Implementation of TRestAxionOpticsMirror to get reflectivity from Henke database

[jgalan]

It implements the class TRestAxionOpticsMirror.

• This class has been fully documented. A web rendered doxygen documentation is already available at: https://sultan.unizar.es/test/classTRestAxionOpticsMirror.html

• A simple validation pipeline has been added. pipeline/metadata/optics/mirrors.py and a basic definition at pipeline/metadata/optics/mirrors.rml.

• A first data set has been added in Adding a first optics relflectivity data file and README axionlib-data#1 for testing. It generates the following image:

Few methods were upgraded to be used in this PR at rest-for-physics/framework#175

[jgalan]

Ups! I guess I have to translate the comment ...
This is great! We have an XXM mirror defined in terms of reflectivity 👍
I think it would be better in linear scale from 0 to 1 with 0.1 intervals, so that we can directly interprete is as 10%,20% ... 100%. But this might be a matter of taste or default.
Ole, ole!

In principle you may recover the canvas in the return of the DrawOpticsProperties function. And you may personalize the aesthetics. Such as changing linear/log scale, or the ranges.

If you draw the canvas in an interactive restRoot session, then you will also be able to inter actuate with the plot. I guess 100% 90% 80% would be interesting because 10-5 reflectivity is basically 0 for us.

Perhaps we could have both easily if needed.

[jgalan]

Bilayer reflectivity has also been implemented.