In attempt to fix a race condition in the tests
* Remove `log4j` deps as redundant: Spring Boot brings them anyway for logback compatibility
* Add `logback-test.xml` to the `spring-websocket-consumer.test` for test race condition failures
* Fix all the Checkstyle violations for those modules
* Introduce a `MosquittoContainerTest` contract into the `spring-function-test-support`
and use it in the MQTT modules
* Fix READMEs for previously migrated modules to auto-configuration
* 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