[Feature] #findOrCreate().

[L-Evg]

Implement #findOrCreate() which shall create entity(is) in target system if there is no entities needed where fetched.

UseCase:
For instance, there is no access to user accounts on Staging/PreProd environment or when you are working with prod DB dump.
You can create new user from tests but DataPool state will differ from real state. So, it'd be good to update DataPool accordingly - to add new user there as well. In this case further tests will be able to reuse this user if necessary.