Add emoji feature to CKEditor 5

Problem/Motivation

CKEditor 44.2 introduces new feature emoji (https://ckeditor.com/docs/ckeditor5/latest/features/emoji.html)

Would be good if we can bring this to core

Steps to reproduce

Proposed resolution

Add emoji feature to core per https://ckeditor.com/docs/ckeditor5/latest/features/emoji.html#installation

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet