Cancel a scheduled publication/take offline

Editors/Admins must be able to cancel a scheduled publication and a scheduled take offline.

Requirements:

For a page with a scheduled publication:

• Replace the publish/take offline options on the Page menu by option:
  'Cancel scheduled publication'
  with icon: calendar-clock

For a page with a scheduled take offline:

• Replace publish/take offline options on the Page menu by:
  'Cancel scheduled take offline'
  with icon: calendar-clock

Rationale:

Scheduled publication and scheduled take offline have been overlooked as requests to be supported in the CM in issue CMS-14010: