start working on dask compatible loo

[OriolAbril]

Description

Initial refactoring to get loo working with dask arrays

Checklist

• Does the PR follow official PR format?
• Does the PR include new or updated tests to cover the new feature (using pytest fixture pattern)?
• Is the code style correct (follows pylint and black guidelines)?
• Is the new feature listed in the New features section of the changelog?

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📚 Documentation preview 📚: https://arviz--2205.org.readthedocs.build/en/2205/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (595fd7f) 86.70% compared to head (b565643) 86.70%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2205   +/-   ##
=======================================
  Coverage   86.70%   86.70%           
=======================================
  Files         122      122           
  Lines       12640    12640           
=======================================
  Hits        10959    10959           
  Misses       1681     1681           

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[cluhmann]

Hey @OriolAbril . Can you let me know how I can help test this? You mentioned that it probably isn't working in its current state, but I'm happy to see what I can do to help out.