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

Remove duplicate code

to avoid lint errors in templates

Disable spelling correction as well
- Use the attributes autocapitalize, autocorrect, spellcheck
- Replace [value]="elementModel.value" with
value="{{elementModel.value}}" to prevent lint errors

belongs to commit #14dcebca

Rearrange the order of function calls

Now named just position.

- Put media files in one separate place
- Add versions to unit definitions
- delete duplicates / useless stuff

The unit definition now has 2 meta-fields: 'type' and 'version'.
The former has the fixed value of 'aspect-unit-definition'.
The latters contains the version without any prefixes, i.e. '1.2.3'.

The sanatizer tries to read the versions of older formats as well and
uses the found version. This is important since the handlePlusOne
method must only run of a specific version (in the old format).

The sanatizer no longer shows any messages and therefore does not need
the MessageService anymore. The information about whether sanatization
happened or not is returned as second parameter for those that are
interested. The editor is, the player is not.

The editor API service now constructs the 'unitDefinitionType'
parameter from both values, resulting in something like
'aspect-unit-definition@1.2.3'.

Use the actual unit reference from UnitService instead of a possibly not 
up to date local variable.