Add Baggage to logback MDC controlled by flag

[adamleantech]

The intention here is to allow users of the java agent to set a VM flag in order to be able to add values in the current Baggage context to MDC for logback. It seemed unwise to turn this on by default - if the application is configured to print all MDC contents (as it often the case with JSON output) then baggage would be logged out by default which may either bloat the logs or result in sensitive data being exposed unitentionally.

Addresses #1391 and #6708

Note that this is my first contribution to this repo, I've done my best to follow the existing approaches to things like testing but would appreciate any feedback.

[linux-foundation-easycla]

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[trask]

thx, this is a great addition!

[mateuszrzeszutek]

Thanks @adamleantech !

[adamleantech]

I'm not sure what is causing the build to fail here and I don't believe I have permissions to retrigger - would appreciate some help getting this clean and merged. @trask @mateuszrzeszutek @laurit

[laurit]

@adamleantech lately we migrated to gradle 8. Unfortunately the org.unbroken-dome.test-sets plugin doesn't work with gradle 8 and the tests using it were migrated to gradle test suites. See https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/instrumentation/log4j/log4j-context-data/log4j-context-data-2.17/javaagent/build.gradle.kts for a sample how the test suites look like. Also see

opentelemetry-java-instrumentation/instrumentation/spring/spring-jms/spring-jms-2.0/javaagent/build.gradle.kts

Lines 52 to 56 in 583e2a7

	configurations {
	named("testReceiveSpansDisabledImplementation") {
	extendsFrom(configurations["testImplementation"])
	}
	}

for how you can copy all test dependencies to test suite.

[mateuszrzeszutek]

(Closing and reopening to trigger checks)

[adamleantech]

I believe the build should be clean now, not sure how to retrigger here, though @trask @laurit @mateuszrzeszutek

[laurit]

closing and reopening to trigger checks

[laurit]

@adamleantech to retrigger checks you can either close and reopen the pull request or push an empty commit

[adamleantech]

@laurit you can see above the I pushed a commit and closed then opened the PR and neither of these triggered a build :-(

[trask]

thx @adamleantech!

[adamleantech]

hooray!