Using disabled cause conflicts with reactive form in player

- Add "isOlderThan" method to the "SanitizationService" to distinguish
old ToggleButtons with the property "option" from new ones
- Use SanitizationService.isUnitDefinitionOutdated in Player to set
the unitDefinitionVersion (should be modified!)

Use css grid instead of flex plus calculating margins in template

Using the html property "disabled" results in a warning message in the
player when reactive forms are used at the same time.

Use the same settings as in simple drop list

ViewEncapsulation.None is required for overriding tooltip

DragNDropValueObject no longer has the stringValue property
but a TextLabel with text

Aslo create new props panel component and move border stylings to 
separate fieldset (wihtin the styling tab).

#291

One as a general label above the table and one for the first column 
heading.

Since this is no proper InputElement separate properties panel inputs 
are used.

#272

To be the same as with Material inputs.

#319

Add new parameter 'itemsPerRow'. This limits the grid columns used, 
making items move to the next row if overextending.

Also simplify component structure.

So TipTap does not moan about empty document.
Put placeholder text in the cloze document instead of the component 
template.

A no longer existing class was used, but turned out to not be necessary 
anyway.

#313

Also add it to the likert row dialog.

#112

Also refactor properties panel and ToggleButton class logic for striking 
values. This now relies more on CSS classes provided by Material instead 
of doing finetuned logic my ourselves. This also allows showing the 
correct preview in the editor.

#287

Turns out the space within the template code are doing this.

#270

Italics indicate that this is not a proper text.

This is needed in on drop logic to set the new value.

The dragged image did contain carry information about it's element.
Also remove useless drag and drop functionality for the placeholder.

- remove prefix 'on'
- split methods

- Remove prefix 'on'

- Remove prefix 'on'

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.

Makes more sense logically to pass the cloze element as a whole instead 
of just the document. Knowing about the document is the responsibility 
of the method not the caller.

- Fix DropLists with copyOnDrop to display a placeholder copy of
dragged elements.
The drop preview is hidden on those lists. It still has to be in the DOM
to be the target for the 'falling' animation of the dragged item,
otherwise it flies to the top left corner of the viewport.