FR: Add support for temporary debug-mode

[dploeger]

We have the requirement to usually start AEM in non-debug mode and only temporarily run it in debug-mode.

Currently, the start-file reads bin/start-env and disallows to set things like DEBUG_PORT using a systemd unit.

It would be great, if the start-env file checks if the environment variables are defined first and only sets them, if not.

Are you okay with that? I could provide you with a PR.

[bdhoine]

I think this should be handled by Puppet rather than an environment variable. If you create a specific profile/env in puppet you can also achieve this and then it would be visible and trackable in source control wheter you provision in debug mode or not. If it would be a zero downtime action it could be a toggle but in this case that does not apply for me.