- When the height of the child elements of a cloze element is increased,
they all now grow out of their center

This was necessary because the new text selection action of the button
is not a navigation.

- Make position props on buttons optional
- Move UIElement creation back to Factory instead of within Section

Also add it to the likert row dialog.

#112

This way elements can handle their logic themselves without having to
rely on outside utility classes.

Also restructure files in common in a more logical way.