Replace `PropertyBasedRequiredBackgroundBootstrapping` with a simpler
`BootstrapExecutorRequiredException` and use a regular failure analyzer
to provide help.
See gh-49733
See gh-49688
Update `spring.data.jpa.repositories.bootstrap-mode` logic
so that:
- A value of `lazy` no longer sets a bootstrap executor.
- A value of `deferred` requires that a bootstrap executor is
ultimately set, and fails with a meaningful message if it is
not.
The logic used to find the AsyncTaskExecutor has now moved to
the `JpaBaseConfiguration` and is triggered by the
`EntityManagerFactoryBuilder` only when background
bootstrapping is required.
Closes gh-49688
Phillip Webb
Andy Wilkinson
Moritz Halbritter