Add DeclarativeConfigContext

[jack-berg]

Refactor declarative config to encapsulate config context and state into a new carrier object, DeclarativeConfigContext.

Benefits:

• Cleans up Factory interface by reducing number of arguments
• Makes it easier to test because SPI loading and closeables tracking is encapsulated in an instance which can be mocked and spied. Previously these were managed via static helper methods.
• Abstracts SPI loading to a single place, making Move declarative config to permanent home #7292 easier
• ~200 fewer lines of code

[codecov]

Codecov Report

Attention: Patch coverage is 91.26214% with 9 lines in your changes missing coverage. Please review.

Project coverage is 90.01%. Comparing base (b468a2e) to head (1a8baf3).

Files with missing lines	Patch %	Lines
...incubator/fileconfig/DeclarativeConfigContext.java	70.96%	8 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #7293      +/-   ##
============================================
- Coverage     90.04%   90.01%   -0.04%     
+ Complexity     6916     6913       -3     
============================================
  Files           787      788       +1     
  Lines         20864    20844      -20     
  Branches       2023     2023              
============================================
- Hits          18788    18762      -26     
- Misses         1439     1442       +3     
- Partials        637      640       +3     

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