This is now done only via the cdkDropListGroup directive which collects 
child drop lists. There is actually no need to connect them manually.

This makes the value unselectable.

#200

Fixes: #203

Move KeyInputModule to the modules subfolder
Create template file for AppComponent

Rename properties and events for keypads

Rename KeyboardComponent to KeypadComponent
Rename KeyboardService to KeypadService
Split LayoutComponent into LayoutPlayerComponent and
LayoutPagesComponent
Prepare the introduction of an additional keyboard

see commit #866a33c6

gridColumnStart: number;
gridColumnEnd: number;
gridRowStart: number;
gridRowEnd: number;

becomes

gridColumn: number;
gridColumnRange: number;
gridRow: number;
gridRowRange: number;

Replace custom pointer events with native pointer events

Improve code and prohibit resizing of section when child element is 
dragged.

Now uses the implicit grid in auto mode.

created with editor 1.26.x

Change translation key and meaning from 'typeAreaWidth' to
'sectionWidth'

By default, text fields and areas only allow the input of keys from the
respective keyboard.

and in ElementFormGroupDirective

Remove case distinction when labeling the page's margin width

This is necessary because the sanitizer returns now an array instead of
the modified unit definition.

Reduce the number of input parameters in FloatingKeyboardComponent
Move double-used method to KeyboardService

Instead, use Textfied component with the property isClozeChild