Use own method `handleRadioButtonGroupElement`

This reverts commit d053d03c.

This feature will first be developed properly in a branch.

Overwriting styles of HTML elements can lead to unwanted side effects

The height of an empty droplist can't be calculated on ios 14
because it's in a flex container

Most importantly dynamic sections are now default.

Cloze documents now use this correctly.

Change import paths of CommonModule files in editor and player

#233

#229

#222

- Fixed dynamicPositioning property of all section children. This 
property was accidentally set with faulty values in the last version.
- Also sanitizes likert and likert row elements, because rows now have a 
TextImageLabel instead of plain text.

The solution is to always show the section menu of the selected section. 
No more hovering shenanigans.

#223