feat(tracing): Add W3C traceparent support

[hangy]

This adds support for propagating the sentry-trace ID as a W3C TraceSpan header to support #2684, loosely based on getsentry/sentry-php@a31d418

I'm not a Python developer by trade and get confused by whitespace instead of curly braces, so please tread carefully. 😉

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 13 lines in your changes missing coverage. Please review.

Project coverage is 80.29%. Comparing base (c361337) to head (0b4084c).
Report is 3 commits behind head on master.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
sentry_sdk/tracing_utils.py	76.00%	1 Missing and 5 partials ⚠️
sentry_sdk/scope.py	54.54%	2 Missing and 3 partials ⚠️
...entry_sdk/integrations/opentelemetry/propagator.py	50.00%	1 Missing ⚠️
sentry_sdk/tracing.py	92.85%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4249   +/-   ##
=======================================
  Coverage   80.28%   80.29%           
=======================================
  Files         142      142           
  Lines       15925    15976   +51     
  Branches     2724     2739   +15     
=======================================
+ Hits        12786    12828   +42     
- Misses       2263     2266    +3     
- Partials      876      882    +6     

Files with missing lines	Coverage Δ
...entry_sdk/integrations/opentelemetry/propagator.py	82.14% <50.00%> (+0.32%)	⬆️
sentry_sdk/tracing.py	78.83% <92.85%> (+0.39%)	⬆️
sentry_sdk/scope.py	85.61% <54.54%> (-0.47%)	⬇️
sentry_sdk/tracing_utils.py	84.96% <76.00%> (+0.18%)	⬆️

[sentrivana]

Hey @hangy, thanks a lot for the work you put into this, but we will not be moving forward with traceparent support in the near future. If we revisit this decision we can revive the PR.