priortize ally ports and close ports (#335)

2x more likely to trade with ports belonging to an ally OR close.
3x more likely to trade with ports belonging to an ally AND close.
Add trading tests

tests/util/TestConfig.ts

@@ -1,7 +1,22 @@
 import { DefaultConfig } from "../../src/core/configuration/DefaultConfig";
 
 export class TestConfig extends DefaultConfig {
+  _proximityBonusPortsNb: number = 0;
+
   samHittingChance(): number {
     return 1;
   }
+
+  radiusPortSpawn(): number {
+    return 1;
+  }
+
+  proximityBonusPortsNb(totalPorts: number): number {
+    return this._proximityBonusPortsNb;
+  }
+
+  // Specific to TestConfig
+  setProximityBonusPortsNb(nb: number): void {
+    this._proximityBonusPortsNb = nb;
+  }
 }