Use Baggage Span Processor to export baggage elements as span attributes.

[puckpuck]

Feature Request

Several OTel SDKs (.NET, Go, Python, JS and Ruby) already support, and Java support is upcoming, to add a Baggage Span Processor as part of the SDKs' built-in extensions.

Use this processor to showcase how users can add a custom or built-in span processor to their SDK when initializing Otel. This will also provide additional value for o11y backends to query the data.