Add feature to `manifold_cbc_bank_plot_mass_model`
Add a feature to manifold_cbc_bank_plot_mass_model to enable plotting the difference between two mass models assuming that both mass models were generated from the same bank.
An example command will be: manifold_cbc_bank_plot_mass_model --prior mdc11_without_cosmology/H1L1V1-O4_MANIFOLD_BANK-MASS_MODEL_WITHOUT_COSMOLOGY-0-2000000000.h5 --post mdc11_with_cosmology/H1L1V1-O4_MANIFOLD_BANK-MASS_MODEL_WITH_COSMOLOGY-0-2000000000.h5 --title "RNPWithZOverWithoutZ" --compare
The behavior of the original script's behavior is preserved; just run manifold_cbc_bank_plot_mass_model mdc11_without_cosmology/H1L1V1-O4_MANIFOLD_BANK-MASS_MODEL_WITHOUT_COSMOLOGY-0-2000000000.h5 to get mass model plots in m1 vs m2 and mc vs chi for a single mass model file.
