[2020] Is there an option to delete a server?

There is an issue open to implement that option, but on low priority as there usually is no real need to delete a world.

Even in that case, worlds ususally do not take up so much space that they really need to be deleted, but as i already said: It will come, just with low priority.

Deleting is possible in 9.0 from ingame, btw.