Add OpenTelemetry log protocol support

[kezhenxu94]

• If this pull request closes/resolves/fixes an existing issue, replace the issue number. Closes [Feature] Support OTLP Native Logging #10752 .
• Update the CHANGES log.

[wu-sheng]

log-otlp.md should be updated according to, especially about

1. Highlighting the OTLP native logging is supported. And add docs about setting up log analysis rules, as well as ref to LAL doc.
2. OLTP SkyWalking log exporter is optional for now.

[wu-sheng]

LGTM

[kezhenxu94]

As said, many of the language SDKs don't support logging feature yet or are experimental stage now, we will need more improvements in the future when they support logging

[wu-sheng]

We don't have to work with OTEL SDKs/Agents anyway. Abou that OTEL, we are always only adopting as much as possible no matter where the source is from and how the format is built.
There are always a group of people who would think the OTEL is somehow a standard or much more meaningful than the other formats.
But from my personal perspective and experiences, there is nothing new there. The metrics format is from Prometheus, the Trace format is from Zipkin, and logs are easy generally text only.

All the points of this kind of support are, we could leverage some existing integrations, which the OTEL community would do. That is the only benefit.

Don't worry whether their agents are supporting or not. The lessons I learned from OT are, these APIs would have special values when they are stale(not updated anymore). Ironically, but true.