chore: Migrate to `commons-configuration2`

[CharlesDuboisSAP]

Context

https://github.com/SAP/cloud-sdk-java/issues/807

We previously used commons-configuration but the new version is at commons-configuration2

Feature scope:

• [ ] Migrate to commons-configuration2

Definition of Done

• [ ] Functionality scope stated & covered
• [ ] Tests cover the scope above
• [ ] ~Error handling created / updated & covered by the tests above~
• [ ] ~Documentation updated~
• [ ] ~Release notes updated~