Out otel support message key

[cb645j]

This is to support sending additional otlp properties derived from log events message properties.
This is related to #8359 and #8552

Testing
Before we can approve your change; please submit the following in a comment:

Example configuration

    [INPUT]
      Name   dummy
      Dummy {"message": "A log message", "span_id": "11aafe22712ca02c", "trace_id": "95e1d11ece6460e7d00c61d45cc195ff"}

    [OUTPUT]
        Name opentelemetry
        Match *
        Log_Level trace
        Host ingest.frontend.com
        Port 443
        Log_response_payload True
        logs_body_key $message
        logs_span_id_message_key span_id
        logs_trace_id_message_key trace_id
        Tls                  On
        Tls.verify           Off

• Debug log output from testing the change

• Attached Valgrind output that shows no leaks or memory corruption was found

If this is a change to packaging of containers or native binaries then please confirm it works for all targets.

• Run local packaging test showing all targets (including any new ones) build.
• Set ok-package-test label to test for all targets (requires maintainer to do).

Documentation

• Documentation required for this feature

Backporting

• Backport to latest stable release.

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

[cb645j]

@nokute78 @sudomateo

[cb645j]

@edsiper