Add optional IB source for data in cache

common/cpp/include/asapo/common/data_structs.h

common/cpp/src/data_structs/data_structs.cpp

consumer/api/cpp/src/tcp_connection_pool.cpp

consumer/api/cpp/src/tcp_connection_pool.h

consumer/api/cpp/src/tcp_consumer_client.cpp

consumer/api/cpp/unittests/mocking.h

consumer/api/cpp/unittests/test_tcp_connection_pool.cpp

consumer/api/cpp/unittests/test_tcp_consumer_client.cpp

receiver/src/main.cpp

receiver/src/receiver_config.cpp

...er/src/receiver_data_server/receiver_data_server_config.h

receiver/src/request_handler/request_handler_db_write.cpp