Added Australia map with 7 bots and their flags (#306)

This is a map of the Australian country. It has 7 bots - the 7 states of
the country. This is my first time making a pull request, so I'm sorry
if i messed something up or something doesn't work.

src/core/game/Game.ts

@@ -51,6 +51,7 @@ export enum GameMapType {
   Mars = "Mars",
   Britannia = "Britannia",
   GatewayToTheAtlantic = "Gateway to the Atlantic",
+  Australia = "Australia",
 }
 
 export enum GameType {

src/core/game/TerrainMapFileLoader.ts

@@ -36,6 +36,7 @@ const MAP_FILE_NAMES: Record<GameMapType, string> = {
   [GameMapType.SouthAmerica]: "SouthAmerica",
   [GameMapType.Britannia]: "Britannia",
   [GameMapType.GatewayToTheAtlantic]: "GatewayToTheAtlantic",
+  [GameMapType.Australia]: "Australia",
 };
 
 class GameMapLoader {