Fixes: https://github.com/spring-cloud/spring-functions-catalog/issues/106
The `AbstractMessageSplitter messageSplitter` injection is too wide,
and if target application has its own splitter bean, it becomes as a candidate.
Since `SplitterFunctionConfiguration` expects only its own beans, rework the logic for `@Qualifier`
and `Optional` to be explicit for expected beans from the `SplitterFunctionConfiguration`.
* 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
