Fix quickstart start

[gregw]

The quick start mechanism was not working well with the /jetty-start script. This PR:

• simplifies how /jetty-start is generated by using the normal docker-entrypoint script
• adds a /jetty-start.args file to record the args used to generate start, so that any runtime changes to args will regenerate.
• setup script jetty-dryrun renamed to jetty-start to more accurately reflect its role.
• quickstart now works with expanded apps that do not have a WAR file