Add ability to limit the # of levels of each dopant

Some dopants (such as Er) have many more energy levels than others. It is unlikely that we get much additional accuracy from including these extra energy levels into the simulation.

Proposed changes:
1) Add the ability to limit the energy levels by energy value.
2) Add the ability to limit the max energy of dopant states in the SpectralKinetics module.


Start by locating the SpectralKinetics module and the code that loads dopant energy levels. Trace how energy values are selected for simulation, then determine where a maximum energy limit can be exposed for dopant states. Done means both proposed limits are supported and the simulation uses the reduced set of levels.

Written by the indexing model from the issue text.