Integration tests: Better Data Initialization and Cleanup

[lsulak]

Background

Currently the IT using Flyway and a real PG on localhost are not really isolated per each test, because they are dependant on Flyway migration scripts that inserts data there.

Expected Behavior

Data insertion should happen before each test and such data should be cleaned-up after each test. Maybe we can even use Balta for this.

https://github.com/AbsaOSS/balta