Create plain wiki pages using the in-place editor

Ideas from Marius:

The simplest solution is probably to:

• force CreateAction to use ActionOnCreate.SAVE_AND_VIEW for wiki pages that support in-place editing https://github.com/xwiki/xwiki-platform/blob/master/xwiki-platform-core/xwiki-platform-oldcore/src/main/java/com/xpn/xwiki/web/CreateAction.java#L265 (of course, when in-place editing is not disabled)
• add the #edit hash / fragment to the redirect URL to trigger the in-place edit mode

Of course, the "downside" is that the page will be saved first, but that shouldn't be very surprising because you previously clicked on the Create button to create the page.

There will be some inconsistency with cases when in-place edit is not the default edit mode for the created page (e.g. because the user prefers the wiki editor). Faking the view mode of a missing (not yet saved / created) page to look as if it was saved, in order to have a seamless transition from inplace edit to view on save, doesn't seem easy to me.

Clicking on Edit / Create for a missing page should first load the missing page rendered with the contentview.vm template so that we can then load the in-place edit mode on it (e.g. we need to have the #xwikicontent div).
Doable, but with a bit more work than saving on create.