Add page action Create

The Create page-action shall allow the user to create a new page, similar to the "add" state of the old Channel Manager's Pages dialog/app.

It is yet t.b.d. if the creating should take place in a dialog or (preferably) a full page. It should be possible to OK or Cancel any changes. After OK-ing changes, the changes should be "pending for publication" and as such influence the Changes menu.