Expand CPS Service Integration Test (framework)

Expand CPS Service Integration Test (framework)

- Created package structure
- Created several test bases
- Created complete test set for Admin service
- Created first test for Data service
- Added human-readable toString() to FetchDescendantsOption for test reporting and debuging purposes
- Renamed fetch descendants (enum) direct children option for consistency with others options
- TODO: Add sample performance test (and base)

Issue-ID: CPS-475
Signed-off-by: ToineSiebelink <toine.siebelink@est.tech>
Change-Id: I75317686161be41662b6bf81314a9cd425ddd6eb