Switch to CKEditor5

[jbalsas]

CKEditor is releasing periodic Developer Previews of its newer version.

We should start playing around with it and make sure we are ready to do the switch when it's released.

This will be the base of our 2.0.0. version.

[jbalsas]

I'm removing the 2.0.0 milestone since the recently released CKEditor5 is changing licensing models, so we probably need to stick with 4.x until we figure it out.

See ckeditor/ckeditor5#991 for more details about it

[duracell80]

Can anyone comment as to the compatibility with IE11 of CK 5 please?
ckeditor/ckeditor5#330

If there is no support for IE11, this could be a deal breaker. Also is CK going to remain the engine under Alloy or is there any discussion taking place to refactor on TinyMCE instead?

[wincent]

Closing this because of the aforementioned licensing issues. Also, no plans to drop support for IE11 as long as it appears in the Liferay DXP compatibility matrix (and it still does).