Support String contentType headers in spring-messaging

After this change DefaultContentTypeResolver supports String-based
"contentType" header values in addition to MimeType-based.

Issue: SPR-11461
Add strictContentTypeMatching converter option

AbstractMessageConverter now supports a strictContentTypeMatching mode
in which the content type of a message must be resolved to a (non-null)
value that matches one of the configured supported MIME types in order
for the converter to be used.

Issue: SPR-11463
Add getMatchingPatterns method to Patterns condition

Issue: SPR-11484