added integration tests for user metadata

broker/src/asapo_broker/database/mongodb.go

broker/src/asapo_broker/database/mongodb_test.go

common/cpp/src/json_parser/rapid_json.cpp

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

tests/automatic/full_chain/CMakeLists.txt

tests/automatic/full_chain/simple_chain/check_linux.sh

...ic/full_chain/simple_chain_usermeta_python/CMakeLists.txt

...ic/full_chain/simple_chain_usermeta_python/check_linux.sh

...full_chain/simple_chain_usermeta_python/check_windows.bat

.../full_chain/simple_chain_usermeta_python/get_user_meta.py

tests/automatic/worker/worker_api/worker_api.cpp

tests/automatic/worker/worker_api_python/worker_api.py

worker/api/python/asapo_worker.pxd

worker/api/python/asapo_worker.pyx.in

worker/tools/folder_to_db/unittests/test_folder_to_db.cpp