[~TASK] FLOW3 (MVC): Changed the order how views are resolved: If a dedicated view exists for the controller / action pair, it is chosen instead of the Fluid Template View.
[+FEATURE] FLOW3 (MVC): The ActionController now allows for specifying view object names for each format, e.g. a specific view for JSON request, another one for HTML etc. Resolves #7113
[!!!]][API] FLOW3 (MVC): Added a new method to the ViewInterface: canRender() must tell if the view is able to render something meaningful for the given controller context.
[~TASK] Fluid (View): Adjusted the template view to the extended ViewInterface.