restructure go files

producer/api/unittests/test_producer.cpp

producer/api/unittests/test_producer_impl.cpp

receiver/src/connection.cpp

receiver/src/connection.h

receiver/src/request.cpp

receiver/src/request.h

receiver/src/request_handler_authorize.cpp

receiver/src/request_handler_authorize.h

receiver/src/request_handler_db_write.cpp

receiver/src/request_handler_file_write.cpp

receiver/src/requests_dispatcher.cpp

receiver/src/requests_dispatcher.h

receiver/unittests/receiver_mocking.h

receiver/unittests/test_connection.cpp

receiver/unittests/test_request.cpp

receiver/unittests/test_request_factory.cpp

receiver/unittests/test_request_handler_authorizer.cpp

receiver/unittests/test_request_handler_db_writer.cpp

receiver/unittests/test_request_handler_file_write.cpp

receiver/unittests/test_requests_dispatcher.cpp