Support Java and MVC namespace view resolution config

This commit improves and completes the initial MVC namespace
view resolution implementation. ContentNegotiatingViewResolver
registration is now also supported.

Java Config view resolution support has been added.
FreeMarker, Velocity and Tiles view configurers are registered
depending on the classpath thanks to an ImportSelector.

For both, a default configuration is provided and documented.

Issue: SPR-7093