The `@MessagingGateway` requires a classpath scanning which is not possible
when we use these function artifacts as dependencies, where packages are fully
different from what target project is built with
* Add `spring-` prefix to function names
Fixes: #9
This commit renames each sub-module in the common, consumer, function
and supplier groups with a prefix of `spring-`.
* Update README.adoc links to new prefixed names
