SPIGOT-6829: Add per-player world border API

By: Parker Hawke <hawkeboyz2@hotmail.com>

paper-api/src/main/java/org/bukkit/Server.java

@@ -604,6 +604,19 @@ public interface Server extends PluginMessageRecipient {
     @Nullable
     public World getWorld(@NotNull UUID uid);
 
+    /**
+     * Create a new virtual {@link WorldBorder}.
+     * <p>
+     * Note that world borders created by the server will not respect any world
+     * scaling effects (i.e. coordinates are not divided by 8 in the nether).
+     *
+     * @return the created world border instance
+     *
+     * @see Player#setWorldBorder(WorldBorder)
+     */
+    @NotNull
+    public WorldBorder createWorldBorder();
+
     /**
      * Gets the map from the given item ID.
      *