[Feature Request] Export chunks

[gentlegiantJGC]

Feature Request

Feature Description

Copying a sub-set of the world's chunks from one world to another would be a useful feature. This may be useful if a user want to prune a very large world down to very little and exporting the small area would be quicker than pruning the rest. This would also mean that the original large world does not need to be duplicated as it may be rather large. This would also be useful for just copying chunks between worlds without having to use the paste menu.