Add Round End gameplay

[Peptide90]

Rounds are currently lasting 4-5+ hours and this is far too long. Rounds should be topping out at 4 hours absolute max.

At the 3 hour mark the round end countdown should be triggered. This allows for up to 30 minutes of events to slowly start happening to increasingly point towards a catastrophe.

By around 3 hours 20, players should get an overt announcement telling them of an impending issue. This may be accompanied by a hint of what the escape vehicle will be so people know where to head to.

3 hours 25 - Escape vehicle arrives or is activated. You now have 5 minutes to get to it or seek appropriate shelter.

3 hours 30 - Catastrophe happens. This can be a nuke detonating on the map, an earthquake or extreme radstorm.

There is then a period of roughly 10 minutes for people to survive in the aftermath of the event. Most people should die in this time if they didn't seek appropriate shelter. Round ends at 3 hours 40 unless extended for some reason.