Rework several aspects of database auto-configuration:
- Use RelaxedPropertyResolver to obtain property values
- Extract EmbeddedDatabaseConnection from EmbeddedDatabaseConfiguration
- Rename several configuration classes for consistency
Issue: #53028397
Various cleanups to the Spring Data JPA example, including:
* Move repositories into service package and make them package private
thus only expose the service interfaces to clients.
* Merge HotelRepository and HotelSummaryRepository and make service
implementations package protected.
* Introduce integration test base class to bootstrap the app as
SpringAppliation.run would.
* Refactor central test case to rather use Spring MVC integration
testing framework.
* Add integration tests for repositories to execute query methods.
