FHI-aims shared library run with mpi4py.

Changes so that the FHI-aims library works with MPI4PY. Needs error management and refinement, but the core functionality is present. Produced as part of discussion around #679.

Example file to use shared library approach: mpi4py_input.py (Run with: mpirun -np 2 python3 mpi4py_input.py. Segfaults on 1 CPU, presumably easy to fix but not addressed yet as just proof of concept)