Propagate context in http2

[grcevski]

This PR adds context propagation with our http2 instrumentation.

[codecov-commenter]

Codecov Report

Attention: 9 lines in your changes are missing coverage. Please review.

Comparison is base (9553916) 79.32% compared to head (842f935) 44.80%.
Report is 9 commits behind head on main.

Files	Patch %	Lines
pkg/internal/ebpf/nethttp/nethttp.go	0.00%	9 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #585       +/-   ##
===========================================
- Coverage   79.32%   44.80%   -34.52%     
===========================================
  Files          69       68        -1     
  Lines        5856     5745      -111     
===========================================
- Hits         4645     2574     -2071     
- Misses        988     3016     +2028     
+ Partials      223      155       -68     

Flag	Coverage Δ
integration-test	?
unittests	44.80% <0.00%> (+0.12%)	⬆️

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[mariomac]

A mazing!

[grcevski]

Thanks Mario!