For all other input assistance presets, the status of the backspace key
is fixed.

- Send metadata as voeReadyNotification to host

- There is a page navigation only for not always visible pages
- Fix initialization of the button's action parameter

- allowReplacement (moved from element to list prop)
- originList and Index are non-optional (means placeholders have to be 
used sometimes)
- Re-introduced the dict of all DropListComponents. This is the only way 
I have found to get a reference to a DropListComponent by ID. This is 
needed for returning to origin. Origin is not actually part of the 
transaction and needs to be fetched from somewhere else. Hence the dict.

- Console statements still present for debugging.

The native browser-drag-and-drop does not work in tablets. Therefore 
back to Material which works.
Features are moved over with the exception of replacing items.

- Copy-Lists now always allow putting items back.

- Renew example files
- Update versions and notes

- Add cdk scrolling strategy to keyboard that brings overlays to
scrolling

- Set the duration of highlighting anchors to 15 seconds
- Disable simultaneous highlighting of anchors

Since buttons can now act as switches for text-element highlighting, it 
is no longer exclusively used for navigation purposes.

Rules for when drop is allowed have been fixed. It is quite complicated 
and therefore a lot of explanatory comments are added.

- improved translation
- add example file

Uses external software 'MathLive'.

Distpacker issues with mathlive have been solved in a custom 
distpacker.ts in scripts-folder. This is now used instead of the 
distpacker from the npm package.

Allows DropListvalueObjects which have this setting to be replaced in
lists which only allow onlyOneItem. When this switch is set, the class
sets the other 2 internal values
(originListID?: string; originListIndex) itself. Those can not be seen
nor changed from outside.

Also refactoring in lots of places around droplists. Better names, 
cleaner structure, comments.

#305

Lists with this setting delete dropped value objects. This allows 
putting items back.
(Only makes sense when used with copyOnDrop. Otherwise there can not be 
duplicate value IDs).

Also improve constructor value checks to correctly handle nullish 
booleans.

#281

This was necessary because the new text selection action of the button
is not a navigation.

The extension is needed to define text areas in the rich text editor
and make them available for the button component

- If this property is set, the input of more characters than specified
in maxLength is prevented
- It also prevents the insertion of text.

The API has been updated and some commands and fields are removed. They 
are kept in for compatibility.

Reads file as base64.

Also rework the GeoGebra dialog to close automatically when a valid 
definition is available, either through pasting or file upload.