Add Jackson 3 support

[tomazfernandes]

The team has agreed to follow the pattern the Spring team did for their migration, in order to support both Jackson v2 and v3 as they do.

The pattern is, roughly:

• Duplicate all classes that use Jackson v2
• Adjust the imports in the duplicate to the new v3 namespace
• Change ObjectMapper usages to JsonMapper in the duplicates

Here's an example with DefaultKafkaHeaderMapper and JsonKafkaHeaderMapper

At some decision points, they check which Jackson versions are in the classpath, such as in MessagingMessageConverter

This is the PR from Spring Kafka's migration for reference: spring-projects/spring-kafka#3996

We could add support by module, or try to add to all modules at the same time.

[ctparton]

Will this be added for 4.0.0 or in a later release?

[MatejNedic]

Hey @ctparton it is aimed for 4.0.0-M2 release