Split semantic conventions package to two to publish stable as 1.x

Is your feature request related to a problem?

Currently, there is one semantic-conventions package with stable and incubating attributes in it. FWIU, there are many deprecated attributes as well inside it from before the concept of incubating was introduced.

When writing instrumentation that wants to only depend on 1.x artifacts, it would be nice if semconv could still be imported.

https://github.com/connectrpc/connect-python/pull/150/changes#diff-e00c59ab50329e61f6ae3512806ae2e2c4e4709ea93571fb5b94354e1bbf6e65

Describe the solution you'd like

I suspect the current semantic-conventions package may not want to be repurposed since it's used too much, even though it's not 1.x. In that case, I propose

• Deprecate opentelemetry-semantic-conventions pypi package
• Add opentelemetry-semconv pypi package which only has stable conventions. Release as 1.x (possibly align the version with OTel spec, or not)
• Add opentelemetry-semconv-unstable pypi package that includes incubating. Using _ to extra-inforce these are unstable could make sense, or the fact that there is unstable in the artifact name could be enough. This artifact is never 1.x.

Describe alternatives you've considered

The current semantic-conventions pypi package could be reworked to only include current, stable attributes. Any user using non-stable attributes would need to migrate. This is fair since it's not 1.x but maybe too destabilizing to the ecosystem

Additional Context

No response

Would you like to implement a fix?

None

Tip

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Start by reviewing how the current semantic-conventions PyPI package is defined and released, then trace where stable, incubating, and deprecated attributes are grouped. Compare that structure with the proposed opentelemetry-semconv and opentelemetry-semconv-unstable packages. Done means the package boundaries, deprecation path, and versioning policy are agreed.