Extract MimeType as a base class of MediaType

MimeType is available in core-spring and does not include support
for quality parameters and media used in HTTP content negotiation.
The MediaType sub-class in org.springframework.http adds q-parameters.
Add header support to WebSocketConnectionManager

Issue: SPR-10796
Allow @ResponseBody on the type level

This change enables having @ResponseBody on the type-level in which
case it inherited and does not need to be added on the method level.

For added convenience, there is also a new @RestController annotation,
a meta-annotation in turn annotated with @Controller and @ResponseBody.
Classes with the new annotation do not need to have @ResponseBody
declared on the method level as it is inherited.

Issue: SPR-10814
Fix bug that ignored custom json prefix

Issue: SPR-10817
Added Java 8 compliant @Schedules container annotation for @Scheduled

Issue: SPR-10532
Introduced  DefaultParameterNameDiscoverer which checks JDK 8's standard reflection first and then falls back to ASM-based debug symbol analysis

Also, StandardReflectionParameterNameDiscoverer calls "Parameter.isNamePresent()" now to return null (and pass on to the next discoverer) if no JDK 8 parameters are available. Note that this requires OpenJDK 8 b100 or higher to compile now.

Issue: SPR-10532