Moved JAVA_OPTS_APPEND out of Dockerfile

[kathirsvn]

What this PR does:
Moved JAVA_OPTS_APPEND out of Dockerfile so we can pass jvm args as required from docker compose file, k8s yaml, etc.

Which issue(s) this PR fixes:
Related to #662

Checklist

• Changes manually tested
• Automated Tests added/updated
• Documentation added/updated
• CLA Signed: DataStax CLA

[jeffreyscarpenter]

Docker compose files are now broken. Log from JSON API container:

2023-11-22 13:03:07 INFO exec -a "java" java -XX:InitialRAMPercentage=50.0 -XX:MaxRAMPercentage=75.0 -XX:+UseG1GC -XX:MinHeapFreeRatio=10 -XX:MaxHeapFreeRatio=20 -XX:GCTimeRatio=4 -XX:AdaptiveSizePolicyWeight=90 -XX:+ExitOnOutOfMemoryError "-Dquarkus.http.host=0.0.0.0 -Djava.util.logging.manager=org.jboss.logmanager.LogManager" -cp "." -jar /deployments/quarkus-run.jar 
2023-11-22 13:03:07 INFO running in /deployments
2023-11-22 13:03:07 Error: Could not find or load main class "-Dquarkus.http.host=0.0.0.0
2023-11-22 13:03:07 Caused by: java.lang.ClassNotFoundException: "-Dquarkus.http.host=0.0.0.0

[kathirsvn]

My bad, fixed it in this PR #678 Can I get a review/approval for that please?