[Core] editor framework setup

[Bistard]

Pull Request Template

Description

Summary:

• Rewrite EVERYTHING related to EditorWidget.

Changes

Type of Changes: new feature / breaking change

1. TODO

Checklist:

• [ ] My code follows the style guidelines of this project
• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules

Reviewers Checklist:

• [ ] Code follows project guidelines and clean code principles
• [ ] Tested on various resolutions and browsers
• [ ] Unit tests have been updated or added, if necessary
• [ ] Documentation has been updated

[Bistard]

The above commit now is able to create a simple functional empty CKEditor when clicking a file✔ But it is just for testing purposes. The related code snippet will be refactored soon.