BB: Added errorbars data and notebook

beaker-notebooks/errorbars_html.bkr

example-data/errorbars/error_bar_binaries.json

...orbars/error_bar_calculations_exciting_results01_new.json

example-data/errorbars/error_bar_input.json

example-data/errorbars/error_bar_monomers.json

example-data/errorbars/error_bar_output_VASP_new.json

example-data/errorbars/gpaw_monomers_unrelaxed_final.json

example-data/errorbars/recommended_POTCAR.dat