!!! FEATURE: Upgrade ckeditor from 16.x to 35.x

[JamesAlias]

closes: #2836

What I did
Upgrade CKEditor to current stable version (35.x) as preparation to introduce new CKEditor Plugins to Neos.

How I did it

How to verify it

[mhsdesign]

our hand copied table and inline widget css may need to be adjusted

neos-ui/packages/neos-ui-ckeditor5-bindings/src/EditorToolbar/TableStyles.vanilla-css

Lines 1 to 3 in 7665b05

	/* This CSS code was extracted by hand from CKE build and some colors were altered.
	It's not worth to set up proper CKE theme build as we only need this code for the table feature currently.
	Feel free to remove it and setup a proper CKE styles build together with a custom theme. */

neos-ui/packages/neos-ui-guest-frame/src/style.css

Line 45 in 7665b05

:global(.ck-content .table table td) {

a note about updating ck: https://neos-project.slack.com/archives/C07QEQ1U2/p1664789241021679?thread_ts=1664545321.750739&cid=C07QEQ1U2

(from @Reinmar )

[JamesAlias]

Will give it a go again when we merged the build stack update. #3200

[crydotsnake]

Hello everyone!

Since #3200 is merged, can we start this topic again?

[mhsdesign]

I know @markusguenther experimented also a bit already but stopped eventually, maybe you (markus) can document the hurdles you found in #2836?

But sure this project can be continued ^^ I currently am focused on neos 9 but feel free to experiment ;)