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!)

The equality check compares the reference of the array and not the
values of the array.

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.

Move label creation to ElementFactory.

No way has been found to have an abstract static method for 
OptionElement's label generation, therefore silence the linter.
Same for getElementComponent.

This is only useful in CompoundElements. So use checks for that class 
instance.

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

Now checks when creating or updating object if IDs are okay.

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

#313

Initialize to null, to be able to differentiate in the props panel.

Also improve props panel layout by always showing all fields and 
disabling them if needed instead of hiding them.

Fix translation.

#318

sanatizer
TextImageLabel:
 position -> imgPosition

DragNDropValueObject
 stringValue -> text
 imgSrcValue -> imgSrc

RadioButtonGroupComplexElement
 columns -> options

Likert
 columns -> options

#293

Also add it to the likert row dialog.

#112