start working at ingest modes

common/cpp/include/common/data_structs.h

...ples/producer/dummy-data-producer/dummy_data_producer.cpp

producer/api/include/producer/common.h

producer/api/include/producer/producer.h

producer/api/src/producer_impl.cpp

producer/api/src/producer_impl.h

producer/api/unittests/test_producer.cpp

producer/api/unittests/test_producer_impl.cpp

producer/event_monitor_producer/src/main_eventmon.cpp