Added macros to generate the NeuLAND ROOT geometry with 26 planes

[jose-luis-rs]

New ROOT geometry provided by Igor with 26 planes for NeuLAND

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Checklist:

• [x] Rebased against dev branch
• [x] My name is in the resp. CONTRIBUTORS/AUTHORS file
• [x] Followed the seven rules of great commit messages

[YanzhaoW]

Is there any cmake cache variable I can set to disable auto generation of the geometry file?

[jose-luis-rs]

Yes, it is already implemented in the dev branch -> #778

[jose-luis-rs]

In the standard root geometry the position (0,0,0) is in the center of the detector as shown in the attached figures.

So, for the use of this root geometry in simulations, the user must define the NeuLAND position in the root macro like this:

run->AddModule(new R3BNeuland(fNeuLandGeo, {0., 0., fDistance}));

where fDistance is the distance with respect to the nominal target position.