Format and lint the code base

[maximlt]

Flake8 was almost entirely disabled. This PR introduces ruff as both the linter and formatter. It is set up with pre-commit. I haven't extended the list of linting rules, but planning to do that in the future (after the next release). I have opted for formatting with single quotes as that was the most used kind of quote in the code base, I'm also fine with double quotes if someone prefers that.

[codecov]

Codecov Report

Attention: Patch coverage is 79.39042% with 142 lines in your changes are missing coverage. Please review.

Project coverage is 87.36%. Comparing base (22cc48b) to head (44c6193).

Files	Patch %	Lines
hvplot/converter.py	74.34%	39 Missing ⚠️
hvplot/plotting/core.py	73.68%	15 Missing ⚠️
hvplot/tests/test_links.py	30.00%	7 Missing ⚠️
hvplot/__init__.py	61.53%	5 Missing ⚠️
hvplot/intake.py	0.00%	5 Missing ⚠️
hvplot/networkx.py	58.33%	5 Missing ⚠️
hvplot/util.py	79.16%	5 Missing ⚠️
hvplot/cudf.py	0.00%	4 Missing ⚠️
hvplot/plotting/andrews_curves.py	20.00%	4 Missing ⚠️
hvplot/plotting/parallel_coordinates.py	20.00%	4 Missing ⚠️
... and 27 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1320      +/-   ##
==========================================
- Coverage   87.40%   87.36%   -0.05%     
==========================================
  Files          50       50              
  Lines        7458     7471      +13     
==========================================
+ Hits         6519     6527       +8     
- Misses        939      944       +5     

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[philippjfr]

Looks great, thank you!