Development: Add Campaign supported for 6 UI Pages and Assets apps, no bootstrap files, just decorations
*available only in pages, assets app since 2.0.1
*add the action by decorations or modifying app definition
Documentation needed: Link to or reuse the current docu in the authoring section, maybe adding a subpage "Campaigns" to the publishing folder. Merge to the dev/6.2.28 branch because MGNLCAMPU-97 will be released with the next version.