compare perf/overhead of the distro

- We should be comparable with the vanilla OTel SDK
- For interest sake, compare to the classic APM agent.

Update (2025-12-04):
- A possible deliverable here is a doc similar to EDOT Java's overhead.md (https://github.com/elastic/elastic-otel-java/blob/main/docs/reference/edot-java/overhead.md) to explain/introduce to users the expected overhead to their app in using this agent.