[Spring Boot] Added business-level component scanning.

Now folks can enable scanning of their business components by setting `io.fabric8.process.spring.boot.container.basepackage` system property on the deployed Spring Boot jar:

    java -jar my-fabric-managed-spring-boot-app.jar -Dio.fabric8.process.spring.boot.container.basepackage=com.company.project

Thanks to this, no custom wiring is needed in order to load project-level components in Fabric-managed Spring Boot jars.