Restore the FlexLayout and related classes from version 1.x

[vegegoku]

The FlexLayout and FlexItem classes were removed in version 2.x and replaced with new approach using css classes, though the new approach is a lot more flexible and requires way less typing some users might still want to use old approach with classes and method calls, the thing to notice that for this case FlexLayout was a special case since it was the only component that is actually just a set of css classes applied through some method and does not provide any specific functionality, for example comparing it an alert or a card or any other component unlike those it is just a div and a set of methods to set some css on that div. that was the main reason to remove it, so with the new approach it can be any element not just a div and it can take any Flex related css even if there is no method is supplied for that css.