Add integration tests for JDBC repo module

[pavelhoral]

In this issue I would like to explore the possibility of adding Testcontainers based integration tests for openidm-repo-jdbc module.

Motivation

I would like to refactor openidm-repo-jdbc module and I would also like to do it in a safe way in relation to supported databases. It would be very helpful to have a way to automatically test integration with all the supported databases.

Approach

Database integration testing can be done either inside dedicated GitHub CI pipeline or on module level within Maven verify phase. I would like to explore the latter - i.e. add failsafe test phase that would test against Testcontainers.

Output

This issue should explore:

• possibility of adding verify test phase to a single module
• possibility of using Testcontainers inside integration tests
• how well Testcontainers play with GitHub pipeline (mainly caching)

This issue is definitely open for discussion, all comments are welcome.

[pavelhoral]

This has been already solved #169 (and was duplicated in #115).