Drop React FAB dependency by replacing ReactAdapter with vanilla component

[Totremont]

Feature proposal

The current implementation introduces a new layer of complexity because it requires writing a communication bridge adapter between the server and the client. For example, I found it problematic to embed this add-on using a WebComponentExporter because some styling and custom .js breaks when everything is wrapped under the web-component shadow dom.
I don't find strong arguments for using a React adapter to implement this component, Vaadin already contains most components required by default. The dragabble aspect can be achieved using a combination of .executeJs, client callable methods and Drag Source, which seems promising.
A simple Vaadin component is easier to maintain, has a simplified state management and does not require npmPackage annotations

Describe solution expectations

Replace the Fab with a combination of .executeJs, client callable methods, Drag Source and the corresponding styling, obviously

Additional information

No response