Reworked IO Port to handle StorageChannels better. (#3284)

* Reworked IO Port to handle custom StorageChannels in a better way.
* Added a transferFactor to `IStorageChannel` to allow addons to speedup the IO Port to transfer faster. E.g. 1000 mB fluid as fast as transfering 1 bucket (item) per operation, not just 1 mB. 
* Also some changes to avoid moving fluids being 1000x as energy expensive as items.

src/api/java/appeng/api/storage/IStorageChannel.java

@@ -43,6 +43,19 @@ import appeng.api.storage.data.IItemList;
 public interface IStorageChannel<T extends IAEStack<T>>
 {
 
+	/**
+	 * Can be used as factor for transferring stacks of a channel.
+	 * 
+	 * E.g. used by IO Ports to transfer 1000 mB, not 1 mB to match the
+	 * item channel transferring a full bucket per operation.
+	 * 
+	 * @return
+	 */
+	default int transferFactor()
+	{
+		return 1;
+	}
+
 	/**
 	 * Create a new {@link IItemList} of the specific type.
 	 *