N°9128 - Update CKEditor5 to v48

[steffunky]

Base information

Question	Answer
Related to a SourceForge thread / Another PR / Combodo ticket?	N°9128
Type of change?	Enhancement

Objective (enhancement)

Update CKEditor 5 from v41.4 to v48.0

Proposed solution (bug and enhancement)

Follow CKEditor v48 upgrade guide, only import CKEditor5 npm package, remove most of webpack use (we still need it to get a build), replace our custom Maximize plugin with the new default Fullscreen plugin
Adapt changes required in iTop's code
Fix issues due to bad SCSS

Checklist before requesting a review

• I have performed a self-review of my code
• I have tested all changes I made on an iTop instance
• Would a unit test be relevant and have I added it?
• Is the PR clear and detailed enough so anyone can understand without digging in the code?

Checklist of things to do before PR is ready to merge

• Wait for N°9128 - Update CKEditor5 to v48 ckeditor5-itop-build#5 to be merged so we can pull a build
• Wait for N°9128 - Fix pseudo selector and attribute selector throwing Array to string conversion combodo-itop-libs/scssphp#1 to be merged so we can compile v48 CSS
• Make variables where needed in backoffice SCSS
• Overload SCSS variables in portal so we have the same HTML display in the editor