Include 'es-mda' method in ert/docs/advanced folder examples

[ajikmr]

Hello. Examples in the folder 'ert/docs/advanced' show 'ensemble_smoother' and 'iterative_smoother' methods. It will be good to add 'es-mda' to the same for clarity and comparison purpose.

Also, importing 'ies' does not work. Instead '_ies' works.

Thanks.