add tests

broker/src/asapo_broker/database/mongodb.go

broker/src/asapo_broker/database/mongodb_test.go

consumer/api/cpp/src/server_data_broker.cpp

consumer/api/cpp/unittests/test_server_broker.cpp

tests/automatic/consumer/consumer_api/check_linux.sh

tests/automatic/consumer/consumer_api/consumer_api.cpp

tests/automatic/consumer/consumer_api_python/check_linux.sh

tests/automatic/consumer/consumer_api_python/consumer_api.py