Ensemble Move short-task

[amandarichardsonn]

The Ensemble class is moved to core/builder/ in this PR -> as_jobs is changed to build_jobs -> and documentation is updated.

[codecov]

Codecov Report

Attention: Patch coverage is 78.57143% with 3 lines in your changes missing coverage. Please review.

Project coverage is 46.28%. Comparing base (cce16e6) to head (8144d51).
Report is 15 commits behind head on smartsim-refactor.

Files with missing lines	Patch %	Lines
smartsim/_core/utils/serialize.py	0.00%	2 Missing ⚠️
smartsim/entity/entity.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@                  Coverage Diff                  @@
##           smartsim-refactor     #714      +/-   ##
=====================================================
+ Coverage              40.45%   46.28%   +5.82%     
=====================================================
  Files                    110      107       -3     
  Lines                   7326     6462     -864     
=====================================================
+ Hits                    2964     2991      +27     
+ Misses                  4362     3471     -891     

Files with missing lines	Coverage Δ
smartsim/_core/control/manifest.py	48.64% <100.00%> (+2.15%)	⬆️
smartsim/_core/launcher/step/step.py	42.85% <100.00%> (+0.17%)	⬆️
smartsim/builders/__init__.py	100.00% <100.00%> (ø)
smartsim/builders/ensemble.py	91.39% <100.00%> (ø)
smartsim/builders/utils/strategies.py	100.00% <ø> (ø)
smartsim/entity/__init__.py	100.00% <ø> (ø)
smartsim/entity/entity.py	75.00% <50.00%> (+9.09%)	⬆️
smartsim/_core/utils/serialize.py	34.00% <0.00%> (-0.70%)	⬇️

... and 8 files with indirect coverage changes

[mellis13]

LGTM