This should not ever be used in production!!
This setting is intended for testing so you can try out converting your world
without actually modifying the world files.
This will add some additional overhead to your world, but you're
just testing anyways so that's not a big deal :)
Will store in a folder named after the current version.
PlayerData and Data folders are copied on server start, so there
may be some delay there, but region files are only copied on demand.
This is highly experiemental so backup your world before relying on this to not modify it
Aikar