Improves comments for Stargate events, and adds a new event for teleporting entities

Adds information about what events can be used for
Tries to clarify event comments where possible
Renames The StargatePortalEvent to StargatePlayerPortalEvent
Adds StargateEntityPortalEvent
Makes the StargateEntityPortalEvent trigger whenever a vehicle is teleported
Removes the unused event name for all events

src/main/java/net/knarcraft/stargate/event/StargateEvent.java

@@ -16,10 +16,9 @@ public abstract class StargateEvent extends Event implements Cancellable {
     /**
      * Instantiates a new stargate event
      *
-     * @param event  <p>UNUSED</p>
      * @param portal <p>The portal involved in this stargate event</p>
      */
-    StargateEvent(String event, Portal portal) {
+    StargateEvent(Portal portal) {
         this.portal = portal;
         this.cancelled = false;
     }