Remove FreeMarker/Velocity/TilesConfigurer MVC config

After some further discussion:

The MVC config simplifies ViewResolver configuration especially where
content negotiation view resolution is involved.

The configuration of the underlying view technology however is kept
completely separate. In the case of the MVC namespace, dedicated
top-level freemarker, velocity, and tiles namespace elements are
provided. In the case of the MVC Java config, applications simply
declare FreeMarkerConfigurer, VelocityConfigurer, or TilesConfigurer
beans respectively.

Issue: SPR-7093