JAVA_HOME should be available from the ROCK

[zmraul]

The charm is currently setting JAVA_HOME in /etc/environment and the Pebble layer env directly:

. . .
layer_config: pebble.LayerDict = {
            "summary": "kafka layer",
            "description": "Pebble config layer for kafka",
            "services": {
                    . . .
                    "environment": {
                        . . .
                        "JAVA_HOME": "/usr/lib/jvm/java-17-openjdk-amd64",
                        . . .
                    },
                }
            },
        }
        return Layer(layer_config)

This env should be readily available during the ROCK deployment.

Solution

1. Add JAVA_HOME to rockcraft.yaml on kafka-rock. See ZooKeeper equivalent
2. Remove hardcoded references to java home from the charm code.

[github-actions]

https://warthogs.atlassian.net/browse/DPE-3448