Manual instrumentation improvements

[antonpirker]

Manual instrumentation for insights module is cumbersome. Update the @trace decorator and make it more powerful. Also add a sentry_sdk.update_current_span(op, name, attributes).

This creates better DX for our users.

[codecov]

Codecov Report

❌ Patch coverage is 47.82609% with 96 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.65%. Comparing base (84adbb7) to head (2011ab4).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
sentry_sdk/tracing_utils.py	44.96%	68 Missing and 14 partials ⚠️
sentry_sdk/api.py	18.18%	9 Missing ⚠️
sentry_sdk/tracing.py	73.33%	2 Missing and 2 partials ⚠️
sentry_sdk/consts.py	88.88%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4648      +/-   ##
==========================================
- Coverage   85.09%   84.65%   -0.44%     
==========================================
  Files         156      156              
  Lines       15797    15944     +147     
  Branches     2671     2723      +52     
==========================================
+ Hits        13442    13498      +56     
- Misses       1578     1654      +76     
- Partials      777      792      +15     

Files with missing lines	Coverage Δ
sentry_sdk/__init__.py	100.00% <ø> (ø)
sentry_sdk/consts.py	99.32% <88.88%> (-0.33%)	⬇️
sentry_sdk/tracing.py	86.02% <73.33%> (-0.45%)	⬇️
sentry_sdk/api.py	84.72% <18.18%> (-5.58%)	⬇️
sentry_sdk/tracing_utils.py	74.62% <44.96%> (-12.12%)	⬇️

... and 2 files with indirect coverage changes