Project restructuring

We completely restructured the project setup to foster code reusability and testability. Therefore, we created a separate library project in which all KPI calculation related functionality will be moved. This MR only contains the structural changes and provides the new project skeleton. The movement of code will be done in a separate MR.

BREAKING CHANGE: we did not yet port the deployment to our new project structure, this also will be addressed in a separate MR.