fix(engine): submit forms with object variables

related to #CAM-2969
chore(clirr): update version for api-compatilibity check
chore(case/form): return proper contextPath for task inside a case

related to CAM-2611
chore(engine): code cleanup

related to CAM-2903
chore(engine): use refactored spin API

related to CAM-2903
test(engine): test removal of spin serialized variable

related to CAM-2834
fix(engine): fix typo in test method names
chore(engine): refactor script parsing, compiling and execution

- script source and resources will now first parsed and optionally
  compiled on first execution

related to #CAM-2863
chore(engine): additional assertions and comments

related to CAM-2843
fix(engine): form property handling

support TaskService.submitTaskForm() for
- CMMN Human Tasks
- Standalone Tasks

related to #CAM-2969, #CAM-2974
fix(engine-rest): correct query method invocation