Add a config option for configuring session timeout

src/main/java/emu/nebula/Config.java

@@ -102,6 +102,7 @@ public class Config {
         public boolean autoCreateAccount = true;
         public boolean skipIntro = false;
         public boolean unlockInstances = true;
+        public int sessionTimeout = 600; // How long to wait (in seconds) after the last http request from a session before removing it from the server
         public int dailyResetHour = 0;
         public int leaderboardRefreshTime = 60; // Leaderboard refresh time in seconds
         public WelcomeMail welcomeMail = new WelcomeMail();

src/main/java/emu/nebula/game/GameContext.java

@@ -77,7 +77,9 @@ public class GameContext implements Runnable {
     // TODO add timeout to config
     public synchronized void cleanupInactiveSessions() {
         var it = this.getSessions().entrySet().iterator();
-        long timeout = System.currentTimeMillis() - TimeUnit.SECONDS.toMillis(600); // 10 minutes
+        
+        int time = Nebula.getConfig().getServerOptions().sessionTimeout;
+        long timeout = System.currentTimeMillis() - TimeUnit.SECONDS.toMillis(time);
         
         while (it.hasNext()) {
             var session = it.next().getValue();