chore: add python deprecation warnings

[roeap]

Description

This PR extends our deprecation warnings for the files and files_by_partitions methods. i.e., a warning is emitted when used, and the function is decorated with @deprecated.

We also tighten the checks in to_pyarrow_dataset to explicitly raise on tables with column mapping or deletion vectors enabled.

Beyond that, there is some code beautification - mostly line breaks in pyo3 signatures.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 73.80%. Comparing base (3583056) to head (92ccf14).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
python/src/reader.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3869   +/-   ##
=======================================
  Coverage   73.80%   73.80%           
=======================================
  Files         151      151           
  Lines       39161    39132   -29     
  Branches    39161    39132   -29     
=======================================
- Hits        28901    28880   -21     
+ Misses       8981     8974    -7     
+ Partials     1279     1278    -1     

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