HIF functionality (new)

[nwlandry]

This PR adds:

• read/write capability of json files according to the HIF standard.
• The __add__ method for IDDict
• Additional bipartite edgelist functionality.
  This replaces PR Added HIF functionality #563

[codecov]

Codecov Report

Attention: Patch coverage is 99.18033% with 1 line in your changes missing coverage. Please review.

Project coverage is 93.15%. Comparing base (7646f9d) to head (502f5c0).
Report is 1 commits behind head on main.

Files	Patch %	Lines
xgi/readwrite/hif.py	98.90%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #572      +/-   ##
==========================================
+ Coverage   92.88%   93.15%   +0.27%     
==========================================
  Files          59       60       +1     
  Lines        4383     4498     +115     
==========================================
+ Hits         4071     4190     +119     
+ Misses        312      308       -4     

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[maximelucas]

What's the difference between the HIF and our own format?

[nwlandry]

What's the difference between the HIF and our own format?

Lots of things. The HIF standard is being developed with 3 other higher-order libraries (and hopefully more in the near future) which means that this will be much more standard. Secondly, HIF has far more features than the format used in XGI-DATA (empy edges, edge-dependent node attributes, directed hypergraphs, etc.) so my hope is that we can finalize the format and then convert the files in XGI-DATA to this sometime down the road.

[maximelucas]

Great, sounds good, thanks a lot.