Integrate @opentelemetry/api-logs package into @opentelemetry/api

[hectorhdzg]

NB: Before opening a feature request against this repo, consider whether the feature should/could be implemented in the other OpenTelemetry client libraries. If so, please open an issue on opentelemetry-specification first.

Once logs API package is stable we should move the code to main api package, creating this issue to track the work.

[dyladan]

I think for future API additions we agreed we want to add an experimental export namespace to the API package. This transition might be a good time to test that flow. e.g. add it to @opentelemetry/api/experimental/logs before stabilization

[github-actions]

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