[IMPROVEMENT] Add spot instance support

Hello, thanks for this.
Can you add the possibility to use spot instance instead of on demand ?

[feydan]

Wouldn't this potentially cause the server to shut down while you are in the middle of playing?

It is a possibility yes (but if you play 2 hours a day, you really have no luck), and aws provide us 2min delay to decide to terminate it or pay more if we want to continue playing. The only thing to know is you have to backup the save on separate volume.
But, spot instance can be 90% discount, that a choice

[feydan]

Got it -- I'm not really actively developing this right now, but I'm happy to take a look at an MR if anyone wants to take a shot at this.