All SDKs and APIs as “stable” for all three signals

[jpkrohling]

@alolita has volunteered to be the sponsor for this.

[svrnm]

@open-telemetry/governance-committee , @open-telemetry/technical-committee:

how much does this involve to also have all three of them documented on opentelemetry.io?

We have a meta issue open to standardize those docs across all languages[^1]:

https://github.com/open-telemetry/opentelemetry.io/issues/3229

I think it would be great to think of "stable" as also having proper end-user-facing documentation.

(cc @open-telemetry/docs-approvers)

[^1]: as far as possible, of course we will anticipate that each language may have there specific wording/details, etc.

[cartermp]

I would say this must involve documentation as well. It shouldn't count as stable until there's docs explaining how to use the APIs.