Added a command to display remaining time

src/main/java/com/alttd/fishingevent/timer/EventManager.java

@@ -80,4 +80,10 @@ public class EventManager {
                         )))));
         server.sendMessage(message.get());
     }
+
+    public Duration getTimeRemaining() {
+        if (duration == null)
+            return Duration.ofMillis(0);
+        return duration.minus(Duration.between(startTime, Instant.now()));
+    }
 }