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%)	⬆️