Make the package dynamic in internal/shared/semconv

[dmathieu]

We need a dynamic package name in internal/shared/semconv, as we can't call the otelhttp/internal/semconvutil package and need to call the package from the instrumentation itself.

[dmathieu]

Ping @open-telemetry/go-approvers for review.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.0%. Comparing base (38dcccc) to head (5ea5dff).
Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #6663   +/-   ##
=====================================
  Coverage   73.0%   73.0%           
=====================================
  Files        189     189           
  Lines      15773   15773           
=====================================
+ Hits       11519   11522    +3     
+ Misses      3920    3918    -2     
+ Partials     334     333    -1     

see 1 file with indirect coverage changes