Implement entity propagation

[gaborcsardi]

New in otel 1.49.0, AFAICT:
https://opentelemetry.io/docs/specs/otel/entities/entity-propagation/
https://github.com/open-telemetry/opentelemetry-specification/blob/main/oteps/entities/0264-resource-and-entities.md

[github-actions]

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[yashikabadaya]

Hi, can I take up this issue?