*Avoid re-rescaling T and p in MOM_EOS_Roquet_rho

  Refactored MOM_EOS_Roquet_rho and MOM_EOS_Roquet_SpV to work directly with
conservative temperatures in [degC] and pressures in [Pa] rather than
normalizing them as in the original Roquet publication.  However, the
coefficients are still set using the values directly copied from that paper, but
rescaled where they are declared as parameters, enabling (or requiring)
compilers to precalculate them during compilation.  These changes are
mathematically equivalent but will change answers at roundoff with these two
equations of state, but they are not believed to be in use yet.