Add initial support for MVC namespace view resolution config

<mvc:view-resolution /> now allows to configure easily
view resolvers.

Issue: SPR-7093
Make Tiles 3 the default implementation in spring-webmvc

Move spring-webmvc-tiles3 content to spring-webmvc, and
create a spring-webmvc-tiles2 module with Tiles 2 support.

Its allows View Resolution to configure Tiles 3 instead of Tiles 2.

Issue: SPR-7093
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
Introduce Freemarker/Velocity/TilesWebMvcConfigurer

This change improves the support for auto-registration of FreeMarker,
Velocity, and Tiles configuration.

The configuration is now conditional not only based on the classpath
but also based on whether a FreeMarkerConfigurer for example is already
present in the configuration.

This change also introduces FreeMarker~, Velocity~, and
TilesWebMvcConfigurer interfaces for customizing each view technology.

The WebMvcConfigurer can still be used to configure all view resolvers
centrally (including FreeMarker, Velocity, and Tiles) without some
default conifguration, i.e. without the need to use the new
~WebMvcConfigurer interfaces until customizations are required.

Issue: SPR-7093
Update ViewResolver registration classes

Following the separation of FreeMarker/Velocity/TilesConfigurer-related
configuration via separate interface, simplify and streamline the
view registration helper classes which no longer have much difference
(most are UrlBasedViewResolver's).

Updates to Javadoc and tests.

Issue: SPR-7093
Update view-resolver namespace

Issue: SPR-7093
Customize concurrency at listener level

Prior to this commit, customizing the concurrency to use fo a given JMS
listener involved to define it in a specific listener-container. As
this is quite restrictive, users may stop using the XML namespace
support altogether to fallback on regular abstract bean definition for
the container.

This commit adds a concurrency attribute to the jms and jca listener
element as well as on the @JmsListener annotation. If the value is set,
it takes precedence; otherwise the value provided by the factory is
used.

Issue: SPR-11988
Add missing 4.1 XSDs

This commit adds the missing 4.1 XSDs for the following components:

* spring-aop
* spring-context
* spring-jee
* spring-lang
* spring-tx
* spring-util

These are strictly identical to the definition of the 4.0 XSDs.

Issue: SPR-11990
Allow to customize separator for messaging destinations

In order to be able to use separators like "." (used by default
by most broker relays) instead of "/" for destination patterns
handling, the PathMatcher used in spring-messaging can now
be customized easily thanks to XML websocket namespace
or JavaConfig.

AntPathMatcher has been updated in order to use the configured path
separator instead of an hardcoded "/" for path concatenation.
Extension handling is now disabled when the "." separator is configured.

Issue: SPR-11660
Update support for using "." as path separator

Issue: SPR-11660
DefaultListableBeanFactory's registerBeanDefinition only calls resetBeanDefinition in case of pre-existing bean definition or pre-existing singleton instance

Issue: SPR-8318
Polishing
Polish WebSocket namespace
Fix white spaces
Add missing handshake-interceptor namespace support

Issue: SPR-11845
Polish WebSocket Java config
Add missing HandshakeInterceptor for STOMP endpoints

Issue: SPR-11845
Merge HandshakeInterceptor-related config updates
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
ConfigurationClassParser processes late-arriving DeferredImportSelectors as regular import selectors

Also contains refined exception handling, treating regular class loading and ASM-based loading consistently in terms of exception wrapping, and always mentioning the current configuration class in all exception messages.

Issue: SPR-11997