Update to Micronaut 4

[tobiasschaefer]

We will probably need to Update Micronaut 4 and Camunda 7.20 together because both switched from javax to jakarta namespace. We will also need to update to Java 17.

[tobiasschaefer]

Here is a PR with work-in-progress: #487

This might help:

• Transactional processing changes in Micronaut 4 micronaut-projects/micronaut-data#1875 (comment)

[nyuuyn]

A fork working on this issue from the branch of @tobiasschaefer is here

[tobiasschaefer]

See also https://micronaut-projects.github.io/micronaut-servlet/latest/guide/#versioning which means we probably also need to update to Camunda 7.20 which switches to jakarta.servlet.

[tobiasschaefer]

We've updated to Camunda 7.20 using the non -jakarta dependencies. We now only need to update Micronaut to version 4.x