Promote EnvironmentResourceProvider to public API

[jack-berg]

Based on this comment.

Users need to reference the FQCN when setting otel.java.enabled.resource.provider and otel.java.disabled.resource.provider. Having .internal. in the package name of such a prominent resource provider isn't a good look, so let's promote EnvironmentResourceProvider to part of the public API.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.84%. Comparing base (c4412f2) to head (7a955c5).
Report is 8 commits behind head on main.

❌ Your project status has failed because the head coverage (89.95%) is below the target coverage (90.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #7052      +/-   ##
============================================
- Coverage     89.96%   89.84%   -0.13%     
+ Complexity     6664     6610      -54     
============================================
  Files           748      740       -8     
  Lines         20088    19981     -107     
  Branches       1970     1966       -4     
============================================
- Hits          18073    17951     -122     
- Misses         1423     1440      +17     
+ Partials        592      590       -2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.