refactor: move OTel hooks to openfeature.contrib.hook

[federicobond]

This PR

• Moves the OTel hooks to the openfeature.contrib.hook namespace, to match the hook namespace in the Python SDK. See chore(main): release openfeature-hooks-opentelemetry 0.1.1 #53 (comment)

Keeps the symmetry between the main and contrib repo namespaces.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.05%. Comparing base (d8e10c7) to head (16db9be).
Report is 16 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #64      +/-   ##
==========================================
+ Coverage   90.55%   93.05%   +2.50%     
==========================================
  Files           8        9       +1     
  Lines         180      216      +36     
==========================================
+ Hits          163      201      +38     
+ Misses         17       15       -2     

Flag	Coverage Δ
unittests	93.05% <100.00%> (+2.50%)	⬆️

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