feat: Conserve Parquet SortingColumns for ints

[coastalwhite]

This PR makes it so that SortedColumns can be used to preserve the sorted flag when reading into Polars. Currently, this is only enabled for integers as other types might require additional considerations. Enabling this feature for other types is trivial now, however.

import polars as pl
import pyarrow.parquet as pq
import io

f = io.BytesIO()

df = pl.DataFrame({
    "a": [1, 2, 3, 4, 5, None],
    "b": [1.0, 2.0, 3.0, 4.0, 5.0, None],
    "c": range(6),
})

pq.write_table(
    df.to_arrow(),
    f,
    sorting_columns=[
        pq.SortingColumn(0, False, False),
        pq.SortingColumn(1, False, False),
    ],
)

f.seek(0)
df = pl.read_parquet(f)._to_metadata(stats='sorted_asc')

Before:

shape: (3, 2)
┌─────────────┬────────────┐
│ column_name ┆ sorted_asc │
│ ---         ┆ ---        │
│ str         ┆ bool       │
╞═════════════╪════════════╡
│ a           ┆ false      │
│ b           ┆ false      │
│ c           ┆ false      │
└─────────────┴────────────┘

After:

shape: (3, 2)
┌─────────────┬────────────┐
│ column_name ┆ sorted_asc │
│ ---         ┆ ---        │
│ str         ┆ bool       │
╞═════════════╪════════════╡
│ a           ┆ true       │
│ b           ┆ false      │
│ c           ┆ false      │
└─────────────┴────────────┘

[codecov]

Codecov Report

Attention: Patch coverage is 94.02985% with 4 lines in your changes missing coverage. Please review.

Project coverage is 80.08%. Comparing base (e29e9df) to head (3cd0c62).
Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-io/src/parquet/read/read_impl.rs	93.54%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #19251      +/-   ##
==========================================
+ Coverage   79.68%   80.08%   +0.39%     
==========================================
  Files        1532     1528       -4     
  Lines      209211   209614     +403     
  Branches     2416     2415       -1     
==========================================
+ Hits       166710   167866    +1156     
+ Misses      41953    41195     -758     
- Partials      548      553       +5     

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[ritchie46]

Nice feature! Still something wrong with the tests...