Deprecate in favor of the CKEditor 5 Plugin Pack

Problem/Motivation

The CKEditor maintainers have added an official pagebreak plugin in the CKEditor 5 Plugin Pack →

Proposed resolution

Deprecated this module and point everyone to CKEditor 5 Plugin Pack instead.

Remaining tasks

Update the module to indicate it's obsolete and unsupported.

User interface changes

n/a

API changes

n/a

Data model changes

tbd