Preliminary baseline Run3 field maps

Adding preliminary versions of the new baseline Run3 maps, for the purpose of producing simulation generated with these maps. These maps are not to be used for official purposes yet.

The added field maps are the base simulated maps coming from TOSCA (the software used to run the field map simulation), with smoothing applied to reduce fluctuations due to the mesh size, and extrapolation applied to have correct field values for points near material boundaries. No correction based on measured field values has been applied to these maps.

Compared to the Run2 maps, a number of changes are made to the material in the simulation to reflect the situation in the cavern more accurately. The material added/changed is listed below

1. The yoke support chariot under the magnet
2. The correct pole face orientation based on survey results
3. The opening of the coil when the magnet is turned on is correctly modelled, based on survey results
4. A correct current description in the coils. In the previous simulation, each block of the coil had a fixed (and shared) value of current density, but the cross section area changes between the blocks, effectively resulting in a description where the current is not conserved. This is corrected by setting the current itself in each block, as opposed to the current density
5. The clamps holding the coils in place
6. Scaffolding around the magnet
7. The bunker
8. Current line feeding the magnet

@mbachmay @fhblanc @mfontana @freiss @sberneta