refactor(python): Move DataFrame.to_numpy implementation to Rust side

[stinodego]

Ref #14334

This is required to facilitate recursive handling of Structs.

[codecov]

Codecov Report

Attention: Patch coverage is 95.86207% with 6 lines in your changes are missing coverage. Please review.

Project coverage is 81.38%. Comparing base (1cdab6f) to head (50ff4d5).
Report is 1 commits behind head on main.

Files	Patch %	Lines
py-polars/src/interop/numpy/to_numpy_df.rs	96.94%	4 Missing ⚠️
py-polars/src/interop/numpy/to_numpy_series.rs	81.81%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #16354   +/-   ##
=======================================
  Coverage   81.37%   81.38%           
=======================================
  Files        1405     1405           
  Lines      183738   183809   +71     
  Branches     2957     2953    -4     
=======================================
+ Hits       149525   149591   +66     
- Misses      33700    33705    +5     
  Partials      513      513           

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