Disable nukes option (#237)

This makes it possible to disable all nukes as well as missile silos
from the game in privat lobbies and singleplayer games

src/core/configuration/Config.ts

@@ -55,6 +55,7 @@ export interface Config {
   percentageTilesOwnedToWin(): number;
   numBots(): number;
   spawnNPCs(): boolean;
+  disableNukes(): boolean;
   bots(): number;
   infiniteGold(): boolean;
   infiniteTroops(): boolean;

src/core/configuration/DefaultConfig.ts

@@ -148,6 +148,9 @@ export class DefaultConfig implements Config {
   spawnNPCs(): boolean {
     return !this._gameConfig.disableNPCs;
   }
+  disableNukes(): boolean {
+    return this._gameConfig.disableNukes;
+  }
   bots(): number {
     return this._gameConfig.bots;
   }