Integrate HIF with more of XGI

[nwlandry]

In preparation for converting XGI-DATA to the HIF standard, this PR does the following:

• Moves the internals of write_hif and read_hif to the convert module as to_hif_dict and from_hif_dict.
• Modifies load_xgi_data to (1) allow HIF format as an input and (2) download/read files in HIF format
• Adds a warning in the write_json and read_json functions notifying users that they are now deprecated.

[codecov]

Codecov Report

Attention: Patch coverage is 94.73684% with 7 lines in your changes missing coverage. Please review.

Project coverage is 93.36%. Comparing base (b74205a) to head (84588a9).
Report is 22 commits behind head on main.

Files with missing lines	Patch %	Lines
xgi/readwrite/xgi_data.py	33.33%	4 Missing ⚠️
xgi/readwrite/hif.py	95.00%	2 Missing ⚠️
xgi/convert/hif_dict.py	98.78%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #613      +/-   ##
==========================================
+ Coverage   93.24%   93.36%   +0.12%     
==========================================
  Files          62       64       +2     
  Lines        4735     4962     +227     
==========================================
+ Hits         4415     4633     +218     
- Misses        320      329       +9     

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[nwlandry]

This partially addresses #605.

[nwlandry]

@maximelucas --- are you able to review this?

[maximelucas]

I can do it yes, if not this week, early next week.
From a quick look already, it would probably be worth adding a general description of the HIF somewhere? Maybe a page in the online docs, or on the existing XGI-DATA page?

[nwlandry]

I can do it yes, if not this week, early next week. From a quick look already, it would probably be worth adding a general description of the HIF somewhere? Maybe a page in the online docs, or on the existing XGI-DATA page?

Great point. I will add this to the XGI-DATA page.

[nwlandry]

@maximelucas I think I addressed all your comments!