EPIC - Decouple Human Tasks from the engine

[elguardian]

The idea is to decouple the lifecycle of the human task from the engine. This can be done in different steps

• UserTask Decouple codegen and interface from engine #1439
• Create endpoints for user task #1484
• Remove obsolete code in process service #1516
• Add Transactional Rest endpoints to UserTasks #1517
• GraphQL external reference id retrieve in data index and audit. #1508
• ProcessServiceImpl user task clean references #1509
• Reenable event test in ProcessTestEvents in kogito-apps #1485
• Clean Up Task Model #1519
• Proper user task exception handling #1520
• Move user task work item handler to its own module to clear boundaries between user task and processes #1521
• Transition object to make extensible user task transition restendpoint #1522
• User task security checks tests. #1510
• Create persistence tier in human task #1486
• Unify task parameters in jbpm-flow #1556
• Marshalling POJO Input/output in user task #1557
• Check process-usertasks-custom-lifecycle-quarkus example after recent HT changes #1515
• Job service uncoupled from processes. #1530
• Deadlines for Human Task #1551