feat: Adds previous island owner to `IslandOwnershipTransferEvent` (#14)

Instead of resolving the previous owner and risk a potential web/api request getting triggert,
although the previous owner might never be used, I decided on just providing the UUID we already have.

The plugins can then still find the (Offline)Player themselves when needed.

src/main/java/com/craftaro/skyblock/api/event/island/IslandOwnershipTransferEvent.java

@@ -5,26 +5,34 @@ import org.bukkit.OfflinePlayer;
 import org.bukkit.event.HandlerList;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.UUID;
+
 public class IslandOwnershipTransferEvent extends IslandEvent {
     private static final HandlerList HANDLERS = new HandlerList();
 
     private final OfflinePlayer owner;
+    private final UUID previousOwnerId;
 
-    public IslandOwnershipTransferEvent(Island island, OfflinePlayer owner) {
+    public IslandOwnershipTransferEvent(Island island, OfflinePlayer owner, UUID previousOwnerId) {
         super(island);
         this.owner = owner;
-    }
-
-    public static HandlerList getHandlerList() {
-        return HANDLERS;
+        this.previousOwnerId = previousOwnerId;
     }
 
     public OfflinePlayer getOwner() {
         return this.owner;
     }
 
+    public UUID getPreviousOwnerId() {
+        return this.previousOwnerId;
+    }
+
     @Override
     public @NotNull HandlerList getHandlers() {
         return HANDLERS;
     }
+
+    public static HandlerList getHandlerList() {
+        return HANDLERS;
+    }
 }

src/main/java/com/craftaro/skyblock/island/IslandManager.java

@@ -520,7 +520,7 @@ public class IslandManager {
             removeIsland(uuid2);
             this.islandStorage.put(player.getUniqueId(), island);
 
-            Bukkit.getServer().getPluginManager().callEvent(new IslandOwnershipTransferEvent(island.getAPIWrapper(), player));
+            Bukkit.getServer().getPluginManager().callEvent(new IslandOwnershipTransferEvent(island.getAPIWrapper(), player, uuid2));
 
             ArrayList<UUID> islandMembers = new ArrayList<>();
             islandMembers.addAll(island.getRole(IslandRole.MEMBER));