refactor(rust!): Move CSV read options from CsvReader to CsvReadOptions

[nameexhaustion]

This is a refactoring to move CSV read options from the CsvReader out to the options struct. This will make it easier to create multiple readers from the same set of options for the new CSV file list reading implementation.

This PR should not change any read behavior, only the way in which a CsvReader is constructed.

Todos after this:

• Try removing the override of the encoding to LossyUtf8 (2 places)

Outdated

This is currently in a state where it builds for Python, and the layout of the options struct is pretty much what I aimed for it to be. What's left is just updating tests / docs on the rust side, but it's will be better to wait until after we review the new layout (as there are a lot of them).

[codecov]

Codecov Report

Attention: Patch coverage is 96.87500% with 15 lines in your changes are missing coverage. Please review.

Project coverage is 80.95%. Comparing base (c4e8678) to head (b6b00c3).

Files	Patch %	Lines
crates/polars-io/src/csv/read/reader.rs	95.95%	4 Missing ⚠️
py-polars/src/dataframe/io.rs	90.24%	4 Missing ⚠️
crates/polars-io/src/csv/read/options.rs	98.83%	2 Missing ⚠️
py-polars/src/batched_csv.rs	92.59%	2 Missing ⚠️
crates/polars-io/src/csv/read/read_impl.rs	88.88%	1 Missing ⚠️
crates/polars-lazy/src/scan/csv.rs	83.33%	1 Missing ⚠️
py-polars/src/lazyframe/visitor/nodes.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #16126      +/-   ##
==========================================
- Coverage   80.96%   80.95%   -0.01%     
==========================================
  Files        1386     1386              
  Lines      178437   178492      +55     
  Branches     2882     2882              
==========================================
+ Hits       144463   144496      +33     
- Misses      33480    33502      +22     
  Partials      494      494              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[ritchie46]

Nice one @nameexhaustion! Great cleanup. 💪