[WIP][AdminBundle] Migrate CKEditor4 to CKEditor5#2820

Draft

dbeerten wants to merge 4 commits intoKunstmaan:masterfrom

dbeerten:ckeditor5

Commits on Nov 9, 2020

Commits on Nov 10, 2020

fix build + wordcount/charcount
dbeerten
committed

Commits on Nov 13, 2020

add custom button to linkUI of CKEditor5
dbeerten
committed