[Outside Request]: Increase spawn distance parameter setting

[Land-Strider]

A3U Spawn Distance parameter has options between 700 and 1.500 meters. A user on Steam has requested if the larger options, up to 3.000 meters, can be added.

Changing this setting to a larger option can potentially alter or break how the Antistasi works, likely cause framerate and script performance issues, but should be still viable to add considering the target audience is low player count servers.

[Land-Strider]

Added 2000, 2500 and 3000 meters spawn distance options on unstable branch commit 4eab261.

Expect heavy performance impact.
Reference from a quick test on local host, single player, sitting at base on a fairly new game:

- 1100m:  28 bots - 101 FPS (AU default spawn distance)
- 1500m:  40 bots -  92 FPS (AU max spawn distance)
- 2000m: 177 bots -  71 FPS
- 2500m: 249 bots -  63 FPS
- 3000m: 382 bots -  52 FPS

Issue can be closed upon merge.