feat(otlp-transformer)!: introduce separate entry-points for OTLP serializers

[pichlermarc]

Which problem is this PR solving?

This is the second-to-last breaking PR for @opentelemetry/otlp-transformer before marking the package as stable (#4582). This solves some issues with rollup, that warns even for code that is dead in the end-user's app. See #5096, #4987.

This PR adds entry points for each signal, each signal gets an entry point for protobuf and json to address #5096 and #4987

The new entrypoint structure is: - /signal, /signal/protobuf, signal/json - experimental signals are prefixed by experimental/ to allow us marking the package stable before the experimental signals are - the spec moves quicker than we do, so I expect there to always be one that is not stable

Closes #5216 Closes #4584 Fixes #5096 Partially addresses #4987

Type of change

• [x] Breaking change (fix or feature that would cause existing functionality to not work as expected)

How Has This Been Tested?

• [x] Unit tests

[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 95.16%. Comparing base (ded89b5) to head (1b00c3c).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5263   +/-   ##
=======================================
  Coverage   95.16%   95.16%           
=======================================
  Files         316      316           
  Lines        9220     9220           
  Branches     2080     2080           
=======================================
  Hits         8774     8774           
  Misses        446      446           

Files with missing lines	Coverage Δ
...ges/exporter-logs-otlp-grpc/src/OTLPLogExporter.ts	100.00% <100.00%> (ø)
...ogs-otlp-http/src/platform/node/OTLPLogExporter.ts	100.00% <100.00%> (ø)
...gs-otlp-proto/src/platform/node/OTLPLogExporter.ts	100.00% <100.00%> (ø)
.../exporter-trace-otlp-grpc/src/OTLPTraceExporter.ts	100.00% <100.00%> (ø)
...e-otlp-http/src/platform/node/OTLPTraceExporter.ts	100.00% <100.00%> (ø)
...-otlp-proto/src/platform/node/OTLPTraceExporter.ts	100.00% <100.00%> (ø)
...porter-metrics-otlp-grpc/src/OTLPMetricExporter.ts	100.00% <100.00%> (ø)
...-otlp-http/src/platform/node/OTLPMetricExporter.ts	100.00% <100.00%> (ø)
...otlp-proto/src/platform/node/OTLPMetricExporter.ts	100.00% <100.00%> (ø)

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[Meligy]

Hello. Any idea when this might be merged and released please?

I suspect it might unblock using the package in nextJS middleware, which runs on Edge runtime, if it's enough for https://github.com/open-telemetry/opentelemetry-js/issues/4987.

[pichlermarc]

Hello. Any idea when this might be merged and released please?

I suspect it might unblock using the package in nextJS middleware, which runs on Edge runtime, if it's enough for #4987.

I'm still waiting on @open-telemetry/javascript-approvers reviews. Once I have an approving review this can get merged. If that happens before Feb 17, we'll release it then.