[FEAT] (ACTORS-2) Add optimization pass to split Project into ActorPoolProject

[jaychia]

Adds logical optimization for splitting a Project with stateful UDFs into a chain of (Project -> ActorPool -> ActorPool -> ... -> Project)

We then rely on ProjectionPushdown rules to optimize this chain (applying column pruning, projection fusion etc).

[codecov]

Codecov Report

Attention: Patch coverage is 92.19653% with 27 lines in your changes missing coverage. Please review.

Please upload report for BASE (main@ae13e22). Learn more about missing BASE report.
Report is 4 commits behind head on main.

Files	Patch %	Lines
...al_optimization/rules/split_actor_pool_projects.rs	93.39%	20 Missing ⚠️
...rc/daft-plan/src/logical_optimization/optimizer.rs	87.50%	5 Missing ⚠️
src/daft-plan/src/logical_optimization/test/mod.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2627   +/-   ##
=======================================
  Coverage        ?   63.56%           
=======================================
  Files           ?      982           
  Lines           ?   112330           
  Branches        ?        0           
=======================================
  Hits            ?    71407           
  Misses          ?    40923           
  Partials        ?        0           

Files	Coverage Δ
daft/udf.py	91.98% <ø> (ø)
src/daft-dsl/src/expr.rs	72.36% <100.00%> (ø)
...logical_optimization/rules/push_down_projection.rs	84.17% <ø> (ø)
src/daft-plan/src/logical_optimization/test/mod.rs	83.33% <0.00%> (ø)
...rc/daft-plan/src/logical_optimization/optimizer.rs	90.22% <87.50%> (ø)
...al_optimization/rules/split_actor_pool_projects.rs	93.39% <93.39%> (ø)

[codspeed-hq]

CodSpeed Performance Report

Merging #2627 will not alter performance

_{Comparing jay/stateful-udf-logical-opt (1fe85eb) with main (ab6d1a5)}

Summary

✅ 10 untouched benchmarks

[desmondcheongzx]

Awesome, thanks for adding the test!