Rename IntegrationConfiguration settings property to settings_dict

[jonathangreen]

Description

Rename the IntegrationConfiguration settings property to settings_dict. This aligns properties on IntegrationConfiguration with those on Library making the code a bit easier to reason about.

This also opens up the opportunity to add a settings property on IntegrationConfiguration that loads the settings class from the settings_dict, similar to the method on Library.

Motivation and Context

While working on PP-94, it was confusing the different properties used to store settings between IntegrationConfiguration and Library now that #1281 has gone in.

How Has This Been Tested?

• Running tests locally

Checklist

• I have updated the documentation accordingly.
• All new and existing tests passed.

[codecov]

Codecov Report

Patch coverage: 93.54% and project coverage change: -0.04% ⚠️

Comparison is base (f25b091) 89.85% compared to head (380eed6) 89.82%.

❗ Current head 380eed6 differs from pull request most recent head 0f51c60. Consider uploading reports for the commit 0f51c60 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1303      +/-   ##
==========================================
- Coverage   89.85%   89.82%   -0.04%     
==========================================
  Files         210      208       -2     
  Lines       28655    28549     -106     
  Branches     6556     6545      -11     
==========================================
- Hits        25749    25644     -105     
  Misses       1893     1893              
+ Partials     1013     1012       -1     

Files Changed	Coverage Δ
api/lcp/mirror.py	85.48% <ø> (ø)
core/opds_import.py	89.29% <0.00%> (ø)
...admin/controller/patron_auth_service_self_tests.py	94.20% <50.00%> (ø)
api/admin/controller/collection_settings.py	91.17% <100.00%> (ø)
api/admin/controller/patron_auth_services.py	91.39% <100.00%> (ø)
api/admin/controller/settings.py	77.96% <100.00%> (ø)
api/lcp/encrypt.py	83.22% <100.00%> (ø)
api/shared_collection.py	93.27% <100.00%> (ø)
core/configuration/ignored_identifier.py	86.66% <100.00%> (ø)
core/model/collection.py	96.03% <100.00%> (ø)
... and 3 more

... and 5 files with indirect coverage changes

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[tdilauro]

Looks good! Just one minor comment, but certainly not a showstopper.

[tdilauro]

Minor: In some cases we're using the variable settings and in others (e.g., core/model/collection.py ll. 363-365), settings_dict. Would be nice to keep these consistent throughout.

[jonathangreen]

This has been hanging out there for awhile, so I'd like to get it merged. I'll try to address this comment in a follow up PR.