feat: export pprof (#517)

[seemk]

Modification of #517

[codecov-commenter]

Codecov Report

Merging #523 (12f3ba1) into main (0ae014e) will increase coverage by 0.02%.
The diff coverage is 55.76%.

@@            Coverage Diff             @@
##             main     #523      +/-   ##
==========================================
+ Coverage   54.87%   54.90%   +0.02%     
==========================================
  Files          28       28              
  Lines        2409     2426      +17     
  Branches      918      919       +1     
==========================================
+ Hits         1322     1332      +10     
- Misses       1087     1094       +7     

Impacted Files	Coverage Δ
src/profiling/types.ts	100.00% <ø> (ø)
src/profiling/OTLPProfilingExporter.ts	48.83% <7.14%> (-9.06%)	⬇️
src/profiling/DebugExporter.ts	30.00% <50.00%> (ø)
src/profiling/utils.ts	89.15% <72.72%> (-10.85%)	⬇️
src/profiling/index.ts	87.65% <100.00%> (+0.15%)	⬆️

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[jtmal-signalfx]

Looks mostly cosmetic, so I'm approving, if there's something bigger hiding in there that I should take a deeper look at, let me know.

[seemk]

I moved it from Rauno's branch so I can edit a bit, for example source.event.period should be a label. Basing memory profiling on this branch as well so I can change stuff if necessary.

[seemk]

Additional changes according to the spec:

• Moved source.event.period from LogRecord to sample labels
• Serialize unknown lines as -1

Plus

• The values received from native profiler can't be undefined, removed unnecessary function types.
• Native side already checks for empty function names, removed adding of (anonymous) due to that

[seemk]

Fixed an issue where the native side was generating all identical stacktraces during the collection step. Happened because the stacktraces array was created outside of the stack line creation loop, thus each stacktrace creation overwrote the same array.