Adding data dir to utils

sempy_core/sempy/core/asteroids/tests/test_transfer_orbit.py

sempy_core/sempy/core/spacecraft/satellite.py

sempy_core/sempy/core/utils/data/ephem_lopg_test_stage.txt

...core/sempy/core/utils/data/ephemeris_propagator_GMAT.json

...ore/sempy/core/utils/data/ephemeris_propagator_SEMAT.json

...ore/sempy/core/utils/data/ephemeris_propagator_SEMPY.json

...core/sempy/core/utils/data/halo_multiple_shooting_sem.mat

sempy_core/sempy/core/utils/data/nro_ms_sem.mat

sempy_core/sempy/core/utils/data/orekit-data.zip

...core/sempy/core/utils/data/propagator_benchmark_semat.mat

sempy_core/sempy/core/utils/data/sh_dyna.mat

...re/sempy/core/utils/data/test_multiple_shooting_cr3bp.mat

sempy_core/sempy/core/utils/orekit_utils.py