Add cloud-stream-kafka back into samples

[onobc]

When combined w/ the changes in https://github.com/spring-cloud/spring-cloud-stream/pull/2456 ./build.sh --aot-only passes.

Next steps are to work on the native image build/run.

@mhalbritter are you ok if we add this back here in spring-native repo and then once it is all working, then I can move it into smoke tests repo?

Steps to test-drive

• get the bits from the above PR locally
• cd spring-cloud-stream/core && ../mvnw clean install -DskipTests
• get the bits from this PR locally
• cd spring-native/samples/cloud-stream-kafka && ./build.sh --aot-only

cc: @OlgaMaciaszek

[mhalbritter]

Sure, merged!

[onobc]

@olegz Here are some direct commands to build time AOT and then runtime AOT

../../mvnw clean package -Dspring-boot.run.jvmArguments="-agentlib:jdwp=transport=dt_socket,address=*:8000,server=y,suspend=n"

java -Dspring.aot.enabled=true '-agentlib:jdwp=transport=dt_socket,address=*:8000,server=y,suspend=n' -jar target/cloud-stream-kafka-0.0.1-SNAPSHOT.jar