Adding the function to add dataframe as pts with nesting in geohy5.py

[LaurentAilleres]

Adding the function to add dataframe as pts with nesting in geohy5.py points a pd.DataFrame() with columns: X, Y, Z, if normal property 'nx', 'ny', 'nz' are present they will be imported. Possibility to nestled into a group with a parent. Parent group must exist prior.

Usage: add_points_from_df('$path_to/project.geoh5", points, overwrite=True, child=ptsname, parent = parentgrp )