Update dependencies

[delucchi-cmu]

• pyyaml was unused
• scipy is no longer a direct dependency (Move sparse histogram to hipscat #405)
• ipykernel is a nice-to-have dependency for folks running inside a jupyter notebook
• but ipywidgets is an even-nicer-to-have dependency
• extras handles the nice-to-haves, including the full suite of fsspec implementations.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.64%. Comparing base (618c14e) to head (54f9317).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #421   +/-   ##
=======================================
  Coverage   98.64%   98.64%           
=======================================
  Files          28       28           
  Lines        1620     1620           
=======================================
  Hits         1598     1598           
  Misses         22       22           

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[github-actions]

Before [618c14e]	After [5f41942]	Ratio	Benchmark (Parameter)
failed	failed	n/a	benchmarks.BinningSuite.time_read_histogram

Click here to view all benchmarks.

[hombit]

Could you please also update Readme and RTD about this new extras?