Object brick - Allowed classes sorting and filtering

What was the issue? 

When allowing classes for objects, the list of classes wasn’t alphabetically sorted and classes that didn’t even have brick fields on them were showing.

How did you solve it? 

A simple query was added to filter and sort classes when they are fetched for object brick.

Why is this fix important?

This fix improves the Pimcore object brick UI.

What do you think about the current direction of the development of the Pimcore platform?

I think Pimcore is going in the right direction.

And if you want to check out this pull request, just follow the link!