Clean up code duplication in low Mach Navier-Stokes physics classes

[pbauman]

In particular, the GRINS::LowMachNavierStokesBase and GRINS::ReactingLowMachNavierStokesBase classes. Problem is I used a different templating scheme for the former. Need to update the former to use the templating scheme of the latter for the material properties. Then should be able to have some commonality between those to put into a base class.