Simulate quartz -> neutron S(Q) using partial g(r) method

TODOs:

• Take the md/in.quartz and fix to get a working simulation
• Compute the partial g(r) and output from rerun on lammps like we did for argon; need 3 - Si-Si, Si-O, and O-O
• Use those partial g(r), apply neutron scattering length weights to each, and calculated neutron G(r)
• Using pystog to transform G(r) -> neutron S(Q)