Change layout to multimaven

`mvn verifiy` ends with error that probably complains that the 2 new modules do not have main class:
[ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:2.6.4:repackage (repackage) on project secret-archive-service: Execution repackage of goal org.springframework.boot:spring-boot-maven-plugin:2.6.4:repackage failed: Unable to find main class -> [Help 1]