Support OTEL_TRACES_EXPORTER in distro

[MrAlias]

Add configuration of the tracing exporter used by the SDK via code options and environment variables.

Required by the GDI specification.

[codecov-commenter]

Codecov Report

Merging #300 (a7fafc5) into main (760f21e) will increase coverage by 0.59%.
The diff coverage is 100.00%.

❗ Current head a7fafc5 differs from pull request most recent head 3f5724a. Consider uploading reports for the commit 3f5724a to get more accurate results

@@            Coverage Diff             @@
##             main     #300      +/-   ##
==========================================
+ Coverage   79.08%   79.67%   +0.59%     
==========================================
  Files          53       54       +1     
  Lines        2634     2696      +62     
==========================================
+ Hits         2083     2148      +65     
+ Misses        511      509       -2     
+ Partials       40       39       -1     

Flag	Coverage Δ
Linux	79.30% <100.00%> (+0.60%)	⬆️
Windows	75.71% <100.00%> (+0.76%)	⬆️
macOS	75.44% <100.00%> (?)

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Impacted Files	Coverage Δ
distro/config.go	100.00% <100.00%> (ø)
distro/exporter.go	100.00% <100.00%> (ø)
distro/otel.go	79.31% <100.00%> (+4.31%)	⬆️

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[pellared]

nice 👍