add scope schema URL and attributes to prom attributes

[zeitlinger]

Reference implementation: https://github.com/open-telemetry/opentelemetry-go/pull/5947

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

[codecov[bot]]

Codecov Report

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

Project coverage is 89.90%. Comparing base (f2f29f5) to head (2edc05f). Report is 54 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #7356      +/-   ##
============================================
+ Coverage     89.77%   89.90%   +0.13%     
- Complexity     6982     7011      +29     
============================================
  Files           797      798       +1     
  Lines         21160    21219      +59     
  Branches       2056     2056              
============================================
+ Hits          18996    19078      +82     
+ Misses         1503     1484      -19     
+ Partials        661      657       -4     

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[pellared]

@zeitlinger, FYI. From https://github.com/open-telemetry/opentelemetry-go/pull/5947#issuecomment-290203538:

SIG meeting: We agreed that this can be merged before updating the spec given we have a preliminary consent with OTel-Prometheus SIG and both exporter and spec are "development".

[zeitlinger]

@zeitlinger, FYI: open-telemetry/opentelemetry-go#5947 (comment)

from that comment

SIG meeting: We agreed that this can be merged before updating the spec given we have a preliminary consent with OTel-Prometheus SIG and both exporter and spec are "development".

[ArthurSens]

This is just a heads-up that the spec change this PR addresses has already been approved and is about to be merged! So you're good to proceed.

If removing the otel_scope_info metric is a breaking change for your SDK, you're empowered to decide how to roll this out!

[zeitlinger]

If removing the otel_scope_info metric is a breaking change for your SDK, you're empowered to decide how to roll this out!

This is not part of this PR - will discuss first how to address this

[zeitlinger]

@jack-berg can you take a look?

[zeitlinger]

@jack-berg please check again