feat(engine): non-fluent case service API

- adds non-fluent methods to
  - set and remove variables
  - create cases by key and id
  - perform plan item lifecycle operations (disable, reenable, manual
    start, complete, close)

related to CAM-2803
fix(engine): deploymentId on TimerEntity after first execution

make sure deploymentId property is not lost after a timer start event
fires for the first time

related to #CAM-2856
chore(engine): remove leftover code
chore(engine): enable TestHelper to find CMMN suffixes for @Deployment

- the @Deployment annotation will now auto detect BPMN and CMMN
  resources based on the method name
- BPMN suffixes are tested prior CMMN suffixes
chore(engine): deprecate getPre/PostParseListener methods
feat(engine): add CmmnTransformListener implementation

related to #CAM-2838