Remove spawn timer on singleplayer

[evanpelle]

Currently there is a spawn timer for singleplayer. This is unnecessary, the game should start when you click to spawn.

The nations should spawn right after the player spawns, so the player doesn't know exactly where the nations will spawn (prevents cheesing by spawning directly next to a nation and taking it out)

[VariableVince]

Maybe a 2-3 seconds grace period timer after the first click? In case you click on the wrong spot by accident. Otherwise you'd have to start a new game again. And then after the 2-3 seconds grace period, place the Nations as mentioned.

[scottanderson]

Something that I think would be cool is if there was a ready/start button.

If everyone in the lobby is ready to start, the game can start before the spawn timer finishes.

[spicydll]

I can take this one @evanpelle

[VariableVince]

It seems there has been no follow-up since almost two months, so i'm going to unassign this. @spicydll If you want it reassigned again, please let us know.

For future reference, this change and its challenges were discussed here in the Dev Discord: https://discord.com/channels/1359946986937258015/1380023230064103565