Currently the user has to set an environment variable like `ENABLE_BUILT_IN_PLUGINS=flink-s3-fs-hadoop-1.19.1.redhat-00002.jar` in their FlinkDeployment. We do not want the user to have to know these redhat-suffixes that could change if we put out a bugfix image, breaking their deployment.

Upstream in the s3 runner we should move the s3 filesystem plugin jar from /opt/flink/opt/ to /opt/flink/plugins at image assembly time.

We should then do the same downstream. This way the plugin will be available out of the box without user intervention.