Chore: upgrade to spring boot 4

[netomi]

This fixes #1843, #1608 .

Changes that are worth to mention:

• use builtin @retryable support instead of explicit spring-retry
• adjust for modularization of spring boot 4
• adjust for changes in hibernate 7 wrt auto-commit in test cases
• use the hibernate version from the spring bom to keep them in sync
• update testcontainers to 2.0.3 and adjust tests accordingly
• replace explicit jackson use from jackson 2 to jackson 3 used by spring boot
• DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES is now disabled by default in jackson 3, no need for a custom ObjectMapper in some cases anymore
• use JsonMapper.shared() or the injected bean instead of creating a new ObjectMapper instance
• update elasticsearch to 9.2.8 to align with the client version that is used by spring boot
• replace all jakarta annotations wrt Nullability to jspecify ones
• some cases were using @NotNull from the jakarta bean validation package which were wrong anyways to the jspecify ones
• keep the bean validation constraints in Property and Entity classes where these annotations are evaluated at runtime

jackson 2 is still inherited from various transitive dependencies, but the application code should not use it but prefer jackson 3 to avoid unexpected side-effects. The annotations are still coming from the 2.21 package as explained in the release notes: https://github.com/FasterXML/jackson/wiki/Jackson-Release-3.0

That will stay like that for a while.

[netomi]

that is now the default in jackson 3