Integration tests: Better Data Initialization and Cleanup

## 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