Replace dragula with SortableJS

Problem/Motivation

Layout Paragraphs currently uses https://github.com/bevacqua/dragula which has no more commits since 2020.

Core switched to sortableJS ( https://www.drupal.org/node/3084730 → ) for example for Layout Builder! And sortableJS has many benefits:

• Touch ready
• Active development
• Core library, no 3rd party dependency management required
• ...

Steps to reproduce

Proposed resolution

Replace the dragula implementation with sortableJS (core/sortable)

Remaining tasks

- Replace the current implementation without interface changes
- Remove dragula

User interface changes

API changes

Data model changes