Mitigate suppressed protected-access errors from pylint

[ankona]

Mitigate the following protected-access errors & remove suppression:

1. EntityList._db_models -> add db_models property returning immutable collection
2. EntityList._db_scripts -> add db_scripts property returning immutable collection
3. Model._db_models -> add db_models property returning immutable collection
4. Model._db_scripts -> add db_scripts property returning immutable collection
5. Add Model.add_ml_model_object passthrough to _append_db_model
6. Add EntityList.add_ml_model_object passthrough to _append_db_model
7. BatchSettings._preamble -> add preamble property returning immutable collection

[codecov]

Codecov Report

Merging #341 (d79c18e) into develop (d80bbc0) will decrease coverage by 0.06%.
Report is 1 commits behind head on develop.
The diff coverage is 97.36%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #341      +/-   ##
===========================================
- Coverage    87.31%   87.25%   -0.06%     
===========================================
  Files           59       59              
  Lines         3531     3546      +15     
===========================================
+ Hits          3083     3094      +11     
- Misses         448      452       +4     

Files Changed	Coverage Δ
smartsim/entity/entityList.py	94.44% <85.71%> (+1.11%)	⬆️
smartsim/_core/control/controller.py	84.15% <100.00%> (ø)
smartsim/_core/control/manifest.py	94.05% <100.00%> (ø)
smartsim/_core/generation/generator.py	93.93% <100.00%> (ø)
smartsim/entity/ensemble.py	99.20% <100.00%> (ø)
smartsim/entity/model.py	95.94% <100.00%> (+0.17%)	⬆️
smartsim/settings/base.py	98.31% <100.00%> (+0.02%)	⬆️

... and 1 file with indirect coverage changes

[mellis13]

Thanks for fixing these lint suppressions. It seems like DBModel and DBScript are more visible to the user now that they are properties. Do you think it's worth making a ticket to look through these objects and make sure they have basic user-functionality for inspection (e.g. __str__).

[ankona]

Ticket 511 created @mellis13

[mellis13]

LGTM -- thanks!