Flatten the .m42 data file

The Mind42 native data format (a Mind42 .m42 file) was nested and hierarchical following a JSON file format, retaining metadata about the mind map including number of anonymised identifiers for individual contributors linked to their contributions, the number of individual contributions, the date and time of individual contributions.  However it is not a human-readable file type.

The script flatten_m42_file.py available on the ECOUTER github repository, can be used to used to flatten the native Mind42 data file, creating a human-readable table of the mind map metadata, individual text contributions and preservation of map structure.