[DOCS] Improve java SDK docs for logs.

[nityanandagohain]

Create doc on how to use log appenders and MDC attributes can be exported

https://github.com/open-telemetry/opentelemetry-java-docs/tree/main/log-appender

ContextData lof4j https://github.com/open-telemetry/opentelemetry-java-instrumentation/tree/main/instrumentation/log4j/log4j-context-data/log4j-context-data-2.17/library-autoconfigure logback https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/instrumentation/logback/logback-mdc-1.0/library/README.md

[nityanandagohain]

run your application using this arg -Dotel.instrumentation.logback-appender.experimental.capture-code-attributes=true

https://github.com/open-telemetry/opentelemetry-java-instrumentation/tree/main/instrumentation/logback/logback-appender-1.0/javaagent

[nityanandagohain]

bumping this cc @ankit01-oss