feat(output): add basic opentelemetry output

[Molter73]

Description

This output allows exporting file activity events as opentelemetry logs via otlp to be collected by compatible systems.

TODO:

• Lock changes behind a feature flag
• Add configurability
• Add integration tests
• Add docs on how to use this output

Checklist

• Patch has a change log entry OR does not need one.
• Investigated and inspected CI test results
• Updated documentation accordingly

Automated testing

• Added unit tests
• Added integration tests
• Added regression tests

If any of these don't apply, please comment below.

Testing Performed

TBD

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch mauro/feat/otel-output

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[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 155 lines in your changes missing coverage. Please review.
✅ Project coverage is 30.50%. Comparing base (0116956) to head (486adb1).
⚠️ Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
fact/src/event/mod.rs	0.00%	81 Missing ⚠️
fact/src/event/process.rs	0.00%	39 Missing ⚠️
fact/src/output/otel/mod.rs	0.00%	33 Missing ⚠️
fact/src/output/mod.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #971      +/-   ##
==========================================
- Coverage   32.23%   30.50%   -1.73%     
==========================================
  Files          21       22       +1     
  Lines        2736     2891     +155     
  Branches     2736     2891     +155     
==========================================
  Hits          882      882              
- Misses       1851     2006     +155     
  Partials        3        3              

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