Add new ensembler component

[christopherbunn]

Resolves #1930

[codecov]

Codecov Report

Merging #2653 (5359ef0) into main (5e62757) will increase coverage by 0.1%.
The diff coverage is 99.4%.

@@           Coverage Diff           @@
##            main   #2653     +/-   ##
=======================================
+ Coverage   99.8%   99.8%   +0.1%     
=======================================
  Files        297     302      +5     
  Lines      27741   28128    +387     
=======================================
+ Hits       27664   28050    +386     
- Misses        77      78      +1     

Impacted Files	Coverage Δ
evalml/automl/automl_search.py	99.9% <ø> (ø)
evalml/pipelines/__init__.py	100.0% <ø> (ø)
evalml/utils/gen_utils.py	99.1% <ø> (ø)
evalml/tests/component_tests/test_utils.py	95.3% <40.0%> (ø)
evalml/tests/automl_tests/test_automl_algorithm.py	97.4% <50.0%> (-2.6%)	⬇️
evalml/automl/automl_algorithm/automl_algorithm.py	100.0% <100.0%> (ø)
...valml/automl/automl_algorithm/default_algorithm.py	100.0% <100.0%> (ø)
...lml/automl/automl_algorithm/iterative_algorithm.py	100.0% <100.0%> (ø)
evalml/automl/engine/engine_base.py	100.0% <100.0%> (ø)
evalml/pipelines/component_graph.py	99.8% <100.0%> (ø)
... and 20 more

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[christopherbunn]

Since these are Windows/Conda tests, we might just not get coverage for this section until we merge to main.

[christopherbunn]

Here is the ensembler performance test doc that I have so far. I think that once I get in this PR for looking glass we can get into a deeper analysis of the results and see where the new ensembler ends up relative to the old one.

9/17 - Updated looking glass doc here:

[eccabay]

Nice, this continues to be awesome work! Just left a couple small suggestions and nits.

[eccabay]

Not sure 56 is the correct value?

Addressed comments in this review.