* Remove general (full) keyboard in layout component
* Implement French keyboard component

* Implement as draggable overlay
* Keyboard can be configured as 'mini' or 'full'

* Rename service to `KeyboardService`
* Replace the two fixed rows for upper and lower case letters
of the keyboard with a general row array
* Rename css classes, variables and methods

Accidental closing of the keyboard can happen when the user clicks on
the board under the keys