[BUGFIX] ActionController must use namespaced object view pattern

The ActionController still uses the old pattern like
Tx_@extension_View_@controller_@action@format for resolving
custom view objects. When using a namespaced extension it
must be possible to also use namespaced view objects.
Therefore a new view object pattern has to be introduced:
@vendor\@extension\View\@controller\@action@format

Releases: 6.2, 6.1, 6.0
Resolves: #47609
Change-Id: Iedc6120469f2277b482c5e1c40b89790404e9bbe
Reviewed-on: https://review.typo3.org/21713
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters