chore(REST): provide docs about HistoricActivityStatistics

related to CAM-1769
chore(REST): provide docs about exposed further query parameter

related to CAM-1770
fix(REST): add value type for canceled and completeScope results

related to #CAM-1770
improve(migration-guide): Add patch level upgrade

related to #CAM-1720

- remove chapter Migrate your Process Application
fix(rest/execution): remove unused messageName from body
doc(bpmn/receive): correlate receive task

relates to #CAM-1612