Domain model mappers

[CatalinM89]

As a product owner I want an in-memory persistence service So that we can support the business requirements

Acceptance criteria:

• configure h2 db (with a separate profile for testing)
• add the Customer and Address entities
• add the jpa repositories
• Add a service to support the persistence and retrieval of the data required in the exposed api endpoints
• repository integration tests

Not in scope: scaling and distributed caching (Redis) given the customer volume is expected to be very low and we're not concerned about long-term persistence. A single instance should suffice the needs of the internal app

Story points: 0.5 Sprint : sprint-0

[CatalinM89]

Closing as delivered by issue: https://github.com/CatalinM89/client-data-management/issues/6 pull request: https://github.com/CatalinM89/client-data-management/pull/16