create unique ids

common/cpp/include/io/io.h

common/cpp/include/unittests/MockIO.h

common/cpp/src/system_io/system_io.cpp

common/cpp/src/system_io/system_io.h

receiver/src/data_cache.cpp

receiver/src/data_cache.h

receiver/src/request_handler_db_write.cpp

receiver/src/request_handler_db_write.h

receiver/src/requests_dispatcher.h

receiver/unittests/test_datacache.cpp

receiver/unittests/test_request_handler_db_writer.cpp