Implement stable db semantic conventions

[JamieDanielson]

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This is a tracking issue for updating instrumentations to allow for dual emitting stable and experimental Database attributes.

Add environment variable option OTEL_SEMCONV_STABILITY_OPT_IN that includes database and database/dup options as recommended in the Database Migration Plan.

• database - emit the stable database conventions, and stop emitting the old database conventions that the instrumentation emitted previously.
• database/dup - emit both the old and the stable database conventions, allowing for a phased rollout of the stable semantic conventions.
• The default behavior (in the absence of one of these values) is to continue emitting whatever version of the old database conventions the instrumentation was emitting previously.

Note: This will use a shared SemconvStability enum and function soon to be available for use.