feat: implement OpenTelemetry traces hook

[federicobond]

This PR

• Implements an OpenTelemetry tracing hook according to the semantic conventions for feature flags.

Related Issues

Implements #7

[codecov[bot]]

Codecov Report

Merging #11 (4bbd718) into main (9d73fd7) will decrease coverage by 0.92%. The diff coverage is 83.33%.

@@            Coverage Diff             @@
##             main      #11      +/-   ##
==========================================
- Coverage   88.11%   87.20%   -0.92%     
==========================================
  Files           7        8       +1     
  Lines         101      125      +24     
==========================================
+ Hits           89      109      +20     
- Misses         12       16       +4     

Flag	Coverage Δ
unittests	87.20% <83.33%> (-0.92%)	:arrow_down:

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Files	Coverage Δ
openfeature/contrib/hooks/otel.py	83.33% <83.33%> (ø)

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[federicobond]

@beeme1mr no worries, it was only recently that I moved it from draft and added you as a reviewer.

[federicobond]

I just added a readme entry for the hook and updated its name following your recommendation.