Expeditions: Ability to limit to 1 expedition per origin

[Deenayd]

Later in the game you usually have more planets than expedition slots. If you allow sending expeditions without waiting for all expeditions to return, than bot randomly choses from which origins to try to send expeditions.

You can try to limit minimum amount of transporters to send, but if 1 or 2 expeditions bring you a lot of your primary ships, than it can happen that you have double the required amount available on the planet (or moon). So bot sometimes starts second expedition from such a planet without waiting for previous one to arrive (if he has enough ships available).

It can easily lead to causing an expedition slot to be overhelmed and decrease success chances.

Would be nice to set a flag somewhere that would make bot check if any expedition is still being executed from given origin and skip the origin if it is.