Launch script

[devinrsmith]

For purposes of customizability and extensions (whether property-based, classpath-based, widget-based, or otherwise), we likely need to migrate away from the out-of-the-box entrypoint provided by docker.javaApplication (grpc-api/server/docker/build.gradle)

...
ENTRYPOINT ["java", "-server", "-XX:+UseG1GC", "-XX:MaxGCPauseMillis=100", "-XX:+UseStringDeduplication", "-XX:InitialRAMPercentage=25.0", "-XX:MinRAMPercentage=70.0", "-XX:MaxRAMPercentage=80.0", "--add-opens", "java.base/java.nio=ALL-UNNAMED", "-XshowSettings:vm", "-cp", "/app/resources:/app/classes:/app/libs/*", "io.deephaven.grpc_api.runner.Main"]
...

We likely won't be able to use the out-of-the-box gradle java application plugin either (grpc-api/server/native/build.gradle), as it has a very specific classpath.

Related to:

• Support importing a Deephaven Extension package with hooks in backend and frontend #1511
• Deephaven Extensions #1468
• Add scriptable docker-entrypoint.d, like the nginx docker image provides #1105