Move to junit5 in all framework tests

- Just a migration
- Replace RedisRule with EnabledOnRedis
- Replace MongoDbRule with EnabledOnMongoDb
- spring-statemachine-test and some docs contains refs to junit4
  but those are support packages and will stay in place.
- Fixes #779
- Relates #771

spring-statemachine-data/jpa/src/test/java/org/springframework/statemachine/data/jpa/JpaRepositoryTests.java

@@ -29,7 +29,7 @@ import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;