refactor(python): Improve/fix internal LRUCache implementation and move into "_utils" module

[alexander-beedie]

Rather than take the cachetools dependency, we have an internal LRUCache implementation. I found a few bugs in it and fixed them, and then added all the missing methods so that we can use it as a true drop-in for the cachetools implementation.

Also added a thorough set of unit tests to validate behaviour, and moved it into the "_utils" module as it isn't cloud-specific.

(Once merged, I'll rebase #23809 on this so that PR will work and pass tests).

[codecov]

Codecov Report

❌ Patch coverage is 91.95402% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.41%. Comparing base (fab59cb) to head (7793d34).
⚠️ Report is 14 commits behind head on main.

Files with missing lines	Patch %	Lines
py-polars/polars/_utils/cache.py	91.46%	5 Missing and 2 partials ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #23813   +/-   ##
=======================================
  Coverage   81.41%   81.41%           
=======================================
  Files        1653     1654    +1     
  Lines      224496   224566   +70     
  Branches     2873     2880    +7     
=======================================
+ Hits       182764   182832   +68     
  Misses      41018    41018           
- Partials      714      716    +2     

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[alexander-beedie]

The new linting errors are unrelated; seem connected to #23825 🤔