feat: Add maintain_order parameter to joins

[stijnherfst]

The API docs specify the ordering for left joins as preserving the order of the left Dataframe. In some cases it can be useful to also have this property for other types of joins and in other cases having no required ordering can allow for performance optimizations.

[codecov]

Codecov Report

Attention: Patch coverage is 85.39326% with 26 lines in your changes missing coverage. Please review.

Project coverage is 79.53%. Comparing base (58f763a) to head (9c4b32a).
Report is 7 commits behind head on main.

Files with missing lines	Patch %	Lines
...s/polars-ops/src/frame/join/dispatch_left_right.rs	78.37%	16 Missing ⚠️
crates/polars-ops/src/frame/join/mod.rs	89.74%	4 Missing ⚠️
crates/polars-python/src/conversion/mod.rs	69.23%	4 Missing ⚠️
crates/polars-ops/src/frame/join/args.rs	66.66%	1 Missing ⚠️
crates/polars-ops/src/frame/join/hash_join/mod.rs	96.55%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             main   #20026    +/-   ##
========================================
  Coverage   79.53%   79.53%            
========================================
  Files        1563     1563            
  Lines      217115   217230   +115     
  Branches     2464     2464            
========================================
+ Hits       172679   172772    +93     
- Misses      43876    43898    +22     
  Partials      560      560            

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