feat(repo): add maven file-tree

[joss2002]

Description

Add standard file-tree structure for Maven.

Expected outcome

The project has a standard Maven file-tree, including a pom.xml and the correct src/main and src/test directories, so that it can be built and run by all team members and CI server.

Acceptance criteria

• pom.xml exists at the root of the project
• Directory structure follows Maven conventions:
  • src/main/java
  • src/main/resources
  • src/test/java
  • src/test/resources
• Project can be compiled with mvn compile without errors
• Tests can be run with mvn test (even if empty at this stage)
• Statement of contribution is added on the repository root