Boundary Condition Macro System - NL Function Eval

[KoenigKrote]

NlFunctionEval has a very similar boundary conditions contribution loop to RichardsJacobianEval. For Dirichlet and Flux boundary conditions, the current macro system is adequate. However, the Overland case has a different loop type between a series of BCStructLoops as well as kinematic or diffusive function calls. Another macro needs to be designed to accommodate this and handle the differing loop types.

[KoenigKrote]

Adding two more ApplyBCPatch macros ApplyBCPatch_WithPrecondition and ApplyBCPatch_WithPostcondition gives a way around this.
See
5e2f48f#diff-55628b556d9b946a1ae7b17ddf8823bbR1202
and
8b9bf42#diff-f6d6ed87a5d906d444492623fe85f0c9R1175

For examples