Fix for #110 issue, ValidationException not thrown when Domain has embedded object

[aulea]

In separate commits fixed first also failing tests:

• wrong Rollback and Transaction annotations, will refer now to gorm package
• running all tests together, then there was data corruption - used unique H2 mem database name

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ aulea
❌ Alar Aule

---

Alar Aule seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}