feat(python): Automatically use boto3 / google-auth if installed when scanning cloud

[nameexhaustion]

For AWS, boto3 adds:

• Auto detection and usage of AWS_PROFILE environment variable
• Additionally also parses the aws_session_token from ~/.aws/credentials

This fixes scanning from our internal S3 cloud after the authentication process changes:

>>> pl.scan_parquet(POLARS_S3_PREFIX + "iris.parquet", credential_provider=None).collect()
polars.exceptions.ComputeError: Generic S3 error: Client error with status 403 Forbidden: No Body
>>> pl.scan_parquet(POLARS_S3_PREFIX + "iris.parquet", credential_provider="auto").collect()
shape: (150, 5)
┌──────────────┬─────────────┬──────────────┬─────────────┬───────────┐
│ sepal_length ┆ sepal_width ┆ petal_length ┆ petal_width ┆ species   │
...

We currently error because our rust config builder isn't parsing the aws_session_token from ~/.aws/credentials.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.74%. Comparing base (4b03406) to head (6161097).
Report is 20 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #19677   +/-   ##
=======================================
  Coverage   79.73%   79.74%           
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  Files        1541     1541           
  Lines      212227   212227           
  Branches     2449     2449           
=======================================
+ Hits       169226   169238   +12     
+ Misses      42446    42435   -11     
+ Partials      555      554    -1     

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