feat!: Remove old streaming engine

[orlp]

The old streaming engine was experimental, and deprecated for a while now. It started breaking more and more and becoming a maintenance issue, so we're now removing it.

[codecov]

Codecov Report

Attention: Patch coverage is 53.57143% with 13 lines in your changes missing coverage. Please review.

Project coverage is 80.71%. Comparing base (8387bab) to head (86f27bc).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-plan/src/plans/ir/tree_format.rs	0.00%	4 Missing ⚠️
crates/polars-plan/src/dsl/options/mod.rs	0.00%	2 Missing ⚠️
crates/polars-plan/src/plans/ir/dot.rs	33.33%	2 Missing ⚠️
py-polars/polars/lazyframe/frame.py	50.00%	0 Missing and 2 partials ⚠️
crates/polars-plan/src/plans/functions/mod.rs	0.00%	1 Missing ⚠️
py-polars/polars/_utils/deprecation.py	0.00%	1 Missing ⚠️
py-polars/polars/functions/lazy.py	50.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #23103      +/-   ##
==========================================
+ Coverage   80.23%   80.71%   +0.48%     
==========================================
  Files        1684     1615      -69     
  Lines      223938   217105    -6833     
  Branches     2809     2809              
==========================================
- Hits       179677   175244    -4433     
+ Misses      43601    41198    -2403     
- Partials      660      663       +3     

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