Migrates all tests and fixtures from JUnit 4.x to Jupiter

[codefromthecrypt]

This migrates all tests and fixtures from JUnit 4.x to Jupiter. Notably, this allows packages such as brave-tests to be unlocked from old junit, allowing integration modules like zipkin-gcp to upgrade/

I began by using this command from @TeamModerne, which got surprisingly far despite this being a very complex project.

./mvnw org.openrewrite.maven:rewrite-maven-plugin:run \
  -Drewrite.recipeArtifactCoordinates=org.openrewrite.recipe:rewrite-testing-frameworks:LATEST \
  -Drewrite.activeRecipes=org.openrewrite.java.testing.junit5.JUnit4to5Migration

After that, I focused on the following areas which led to conclusion:

• move to the next minor version as this is not a patch-scoped change
• fix formatting and visibility
• revert mockwebserver3 upgrade as it introduced classpath incompatibility
• port Mockito and nested class junit rules
• address test drift as dubbo tests weren't running before for some reason
• port the maven-invoker-plugin tests
• move kafka tests off kafka-unit which I really couldn't get to work
• port the internal rules, notably JMS took the most time

There are more polishing available, but this PR is already too big to add more, and these things can be done later, anyway.

[codefromthecrypt]

After this, I'll bump any main versions that can be bumped easily and prepare for the next release.

[codefromthecrypt]

thanks for the look, finishing up next!