I have removed all the CKEditor 4 related code from the 2.1.x branch. From no...

I have removed all the CKEditor 4 related code from the 2.1.x branch. From now onwards, the 2.1.x branch will have code related to CKEditor 5 only. 2.0.x branch will have changes related to CKEditor 4.

In case there is a support request for the possibility of using both in a single website, I will explore the submodule approach in that case.