Stabilize opentelemetry-semconv

[jack-berg]

Want to start a conversation about what stands in the way of marking the opentelemetry-semconv artifact as stable. We've come a long way recently, re-organizing by domain, switching from build-tools to weaver based code generation, and changing how we think about deprecated / incubating attributes.

[breedx-splk]

With incubating in place, it seems like most of the roadblocks have been cleared. I suppose the main thing to think about is needing to be able to support future breaking changes though major semver bumps, which should be seldom and annoying at worst?