[Backport 14.6] Create, display and remove campaign schedule

• Add action button to open up schedule form only for xpages that are in 'Core' / 'master' / Not in a project
• Add a form to create a schedule for specific version.
• Display the schedule date for a version in the list
• Allow a user to remove a campaign schedule

 Design: https://bloomreach.invisionapp.com/console/Page-campaigns-cklw2artx0861013ecsun2da1/cklw2askz06gx011k4p9y3lo3/play

The datepickers from Api Token Management can be used as example. For the timepicker we can use a normal mat-input with type="time" or a plain input field with validation.