This holds variable names, taken from the GeoGebra applet, and uses 
those variable values in the value. This makes result analysis easier.

#449

- position
- label
- icon

Absolute position didn't work if the display scaling factor of the
operating system or browser is not 1.

#511

- Remove dynamicPositioning from PositionProperties. This is not 
knowledge that the element needs to know. In the few places it was used, 
it was fixed or solved by asking the containing section about which 
positioning is active.

- Fix and improve cloze child sizing. All can now have dynamic width and 
height.

- Fix empty lines in ClozeDocument rendering

- Editor SelectionService now knows if a cloze child is selected. This 
way the PropertiesPanel can show valid dimension inputs regardless of 
the underlying section.

Also restructure files containing interfaces.

Toolbar is a single word, therefore any capitalized letters are errors. 
No need to sanitize, since this was broken anyway.

#384

- This allows to reset Geogebra to the state defined in the unit
definition

The updateListener does not detect all changes inside a GeoGebra element

- Using the Geogebra method 'getBase64' is very resource intensive.

Move deps only used by geometry to the geometry class and out of the 
parent.

DomSanitizer was a relict and no longer in use.