Integrate updated HED validation library call

[christinerogers]

details to follow here, by me or Kay Robbins @VisLab HED lead

in a nutshell:

currently one file in the javascript file serves as the interface and calls HED Tools (MPM pkg currently)

the idea is to replace this with the HED tools python package at the same time, to include in the new BIDS validator.
Probably straightforward to port over this file used in the javascript validator, for use in python

The HED team is very happy to contribute to this effort, let's coordinate in March for followup.

background:

• hedtags.org
• hedtools.org
• About HED tags in BIDS https://bids-specification.readthedocs.io/en/stable/appendices/hed.html

[VisLab]

The Python hedtools (available on PyPI) provide methods very similar to those used in the HED JavaScript validator (available on npm). We would be happy to adapt if needed. It would be appreciated if you would ping us on any details about the interface when they become available.