chore(engine): remove unnecessary TODO
chore(engine): make variable value subtype resolution transitive

related to CAM-2939
chore(engine): provide constants for serialization dataformats

allows users to use constants when hinting object value serialization
dataformat

related to #CAM-2890
feat(case): provide activity type and description

related to CAM-2871
fix(engine): fix followUpBeforeOrNotExistent expression handling

related to #CAM-3080
fix(engine): fix variable queries with NOT_EQUALS operator

- reworks the query logic such that NOT_EQUALS is matched like EQUALS
  but with the overall condition negated

related to CAM-2939
fix(rest): fix followUpBeforeOrNotExistent expression handling in

related to #CAM-3080
test(engine): add failing test case for boundary end event

related to CAM-3111