Add declarative config support for ExemplarFilter

[jack-berg]

Resolves #7667

[codecov]

Codecov Report

❌ Patch coverage is 88.88889% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.18%. Comparing base (a01288b) to head (839c1bc).
⚠️ Report is 22 commits behind head on main.

Files with missing lines	Patch %	Lines
...on/incubator/fileconfig/ExemplarFilterFactory.java	71.42%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@ Coverage Diff @@ ## main #7769 +/- ## ============================================ + Coverage 90.16% 90.18% +0.02%  - Complexity 7189 7200 +11  ============================================ Files 814 815 +1 Lines 21730 21744 +14 Branches 2129 2130 +1 ============================================ + Hits 19592 19609 +17  + Misses 1469 1468 -1  + Partials 669 667 -2 

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