Move the physical setup of FocalH to a new class

[Bjartensen]

Move the FocalH physical setup and neighbor calculations from cell_main to different classes.

[Bjartensen]

https://github.com/Bjartensen/root-clustering-focalh

Currently requires refactoring ...

Moving the geometry into a class

https://github.com/Bjartensen/root-clustering-focalh/issues/7

Brainstorm focalh geometry header

• geometry::focalh ✓
• detector::focalh
• physical::focalh
• setup::focalh

Class Geometry. Derived class FoCalH.

Class Geometry
    Grid g;
public:
    Geometry();
    virtual bool construct_geometry() = 0;
    get_grid();

Simple class with a Grid and virtual function that sets up the Grid. Then a class FoCalH or FoCal_H.

Class FoCalH : public Geometry
    Grid g;
public:
    bool construct_geometry();
    bool make_cells();
    bool calc_neighbors_for_cell();
    bool calc_neighbors();

[Bjartensen]

8aeed8f3604b31f1ede2aaa50e293164216dafec