Added a readme to briefly describe what's contained in the examples. Added Maven Wrapper to all example projects.
Limit the dependencies of the JDBC based example to sole Spring JDBC (dropping the Spring Data integration as it's not needed for the example. Remove unused, JPA-related property
Switch verification of mock beans as Mockito 5.3.0 uses a different MockMaker by default that doesn't add the explicit interface we have previously checked for.
Remove obsolete init- and destroy method declarations from service bean definitions in examples.
