Add API for ambient mob spawn limit. Adds BUKKIT-2765

By: Travis Watkins <amaranth@ubuntu.com>

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

@@ -648,6 +648,12 @@ public interface Server extends PluginMessageRecipient {
      */
     int getWaterAnimalSpawnLimit();
 
+    /**
+     * Gets user-specified limit for number of ambient mobs that can spawn in a chunk
+     * @returns The ambient spawn limit
+     */
+    int getAmbientSpawnLimit();
+
     /**
      * Returns true if the current {@link Thread} is the server's primary thread
      */
@@ -666,4 +672,4 @@ public interface Server extends PluginMessageRecipient {
      * @return The configured WarningState
      */
     public WarningState getWarningState();
-}
+}