The RC1 version had some websocket issues, that prevented propper websocket communication.
In some cases the SocketJS communication was downgraded to 'xhr_streaming'.
Update SpringBootServletInitializer with separate getConfigClass() and
getAdditionalConfigClasses() methods. This change makes it easier to
use the SpringBootServletInitializer with the common use case of a
single config class.
The management endpoints were still all mixed up
with the user endpoints. Fixed that and extracted
user endpoints in to conditional block so not
protected if path explicitly set to empty string.
[#53029715]
Opinionated defaults for WebSockets:
* If spring-websocket is on the classpath and so is
the Tomcat WSci initializer then it is added to the context
* A DefaultSockJsService is added if none is present
* User has only to define @Beans of type WebSocketHandler with
name starting "/"
* Each one is converted to a SockJsHttpRequestHandler and
mapped to "/<beanName>/**"