feat: Add SQL support for RIGHT JOIN, fix an issue with wildcard aliasing

[alexander-beedie]

• Exposes the right join support added in feat: Add right join support #17441 up to the SQL interface.
• Fixes SQL SELECT right.* returns values from left side in JOIN query #17552, where a SELECT on a single alias.* wildcard would always select from the left-most frame; the columns are now resolved with respect to the alias in all cases.
• Additional test coverage for these cases, and join aliasing in general.

Examples

Establish some test frames:

import polars as pl

df1 = pl.DataFrame({
  "a": [1, 2, 3],
  "b": ["x", "y", "z"],
  "c": [100, 200, 300],
})
df2 = pl.DataFrame({
  "a": [1, 3, 2],
  "b": ["qq", "pp", "oo"],
  "c": [400, 500, 600],
})

Apply a RIGHT JOIN (new feature)...
...returning all cols from the right-most frame (bugfix):

pl.sql("""
  SELECT df2.*
  FROM df1 RIGHT JOIN df2 USING (a) ORDER BY a
""").collect()

# shape: (3, 3)
# ┌─────┬─────┬─────┐
# │ a   ┆ b   ┆ c   │
# │ --- ┆ --- ┆ --- │
# │ i64 ┆ str ┆ i64 │
# ╞═════╪═════╪═════╡
# │ 1   ┆ qq  ┆ 400 │
# │ 2   ┆ oo  ┆ 600 │
# │ 3   ┆ pp  ┆ 500 │
# └─────┴─────┴─────┘

[codecov]

Codecov Report

Attention: Patch coverage is 96.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 79.92%. Comparing base (45a9313) to head (c05a2a0).
Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-sql/src/context.rs	91.66%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main   #19626       +/-   ##
===========================================
+ Coverage   60.10%   79.92%   +19.81%     
===========================================
  Files        1536     1536               
  Lines      211676   211687       +11     
  Branches     2445     2445               
===========================================
+ Hits       127236   169188    +41952     
+ Misses      83885    41944    -41941     
  Partials      555      555               

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