start server databroker

examples/worker/process_folder/process_folder.cpp

tests/worker/connect_multithread/content_multithread.cpp

tests/worker/next_multithread/next_multithread.cpp

worker/api/cpp/CMakeLists.txt

worker/api/cpp/include/worker/data_broker.h

worker/api/cpp/src/data_broker.cpp

worker/api/cpp/src/server_data_broker.cpp

worker/api/cpp/src/server_data_broker.h

worker/api/cpp/unittests/test_worker_api.cpp