Validation framework - transport header support

[c1ly]

Change Summary

• Updated Pipeline, Capture, Generator structs with transport header fields and new functions to allow user to configure transport headers and transport header policies to use

• Updated templates to insert transport headers and transport header policy

What issue does this PR close?

• Closes support transport headers with the validation framework #2704

How are these changes tested?

unit tests and validation test

Are there any user-facing changes?

no

[codecov]

Codecov Report

❌ Patch coverage is 95.38784% with 22 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.14%. Comparing base (bc4cec8) to head (aa7358e).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2733      +/-   ##
==========================================
+ Coverage   88.13%   88.14%   +0.01%     
==========================================
  Files         645      646       +1     
  Lines      248445   248879     +434     
==========================================
+ Hits       218956   219374     +418     
- Misses      28965    28981      +16     
  Partials      524      524              

Components	Coverage Δ
otap-dataflow	89.73% <95.38%> (+0.01%)	⬆️
query_abstraction	80.61% <ø> (ø)
query_engine	90.75% <ø> (ø)
otel-arrow-go	52.45% <ø> (ø)
quiver	92.25% <ø> (ø)

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