prometheus: Add otel_scope_schema_url and otel_scope_[attribute] labels

[pellared]

Towards https://github.com/open-telemetry/opentelemetry-specification/issues/4223 and https://github.com/open-telemetry/opentelemetry-go/issues/5846

• Add instrumentation scope schema URL as otel_scope_schema_url label to otel_scope_info metric
• Add instrumentation scope schema URL as otel_scope_schema_url label to "real" OTel metrics
• Add instrumentation scope attributes as otel_scope_[attribute] labels to "real" OTel metrics

Side notes:

• The exporter does not seem to work correctly if the end user adds e.g. an otel_scope_name attribute. I think the exporter should ignore all attributes with names that have prefix otel_scope_. This scenario is also not covered by the spec.
• I remember that David was also proposing to have the new functionality behind some env var feature toggle

[pellared]

@dashpole PTAL

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 84.6%. Comparing base (ff07838) to head (417330c).

Additional details and impacted files

[](https://app.codecov.io/gh/open-telemetry/opentelemetry-go/pull/5947?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) ```diff @@ Coverage Diff @@ ## main #5947 +/- ## ===================================== Coverage 84.6% 84.6% ===================================== Files 272 272 Lines 22864 22872 +8 ===================================== + Hits 19348 19356 +8 Misses 3172 3172 Partials 344 344 ``` [see 1 file with indirect coverage changes](https://app.codecov.io/gh/open-telemetry/opentelemetry-go/pull/5947/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry)