Add "To Top" button to the manual sort category listing

[nicobatty]

How it looks:

The reason why:

I added this feature on our project because we had a lot of products in manual sort.

When you add a product as Manual sort, it gets to the end of the Manual sort product list and using the drag and drop to get a few products to the top is not really practical and can take some time, especially for a user that is not really good with a mouse.

Technical Details:

I did it and tested it in a few hours because I did not have too much time to spend on this so it might not be perfectly coded. I tried to reuse the API and logic that was currently available but the code could clearly be improved / refactored.

What's missing:

• Hide the button for the element at the top of the list (that is not really a problem though).

[romainruaud]

Seems great !

I'll try to have a look on this one and to test it deeply.

But it's definitely a big THANKS for contributing to our Open Source project :)