fts - check file can be read, implement delete stream from producer

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

common/cpp/include/asapo/common/networking.h

common/cpp/include/asapo/database/database.h

common/cpp/include/asapo/unittests/MockDatabase.h

common/cpp/src/database/mongodb_client.cpp

common/cpp/src/database/mongodb_client.h

file_transfer/src/asapo_file_transfer/server/transfer.go

producer/api/cpp/include/asapo/producer/producer.h

producer/api/cpp/src/producer_impl.cpp

producer/api/cpp/src/producer_impl.h

producer/api/cpp/unittests/test_producer_impl.cpp

receiver/CMakeLists.txt

receiver/src/request_handler/request_factory.cpp

receiver/src/request_handler/request_factory.h

...ver/src/request_handler/request_handler_delete_stream.cpp

receiver/src/request_handler/request_handler_delete_stream.h

receiver/src/request_handler/requests_dispatcher.cpp

receiver/unittests/request_handler/test_request_factory.cpp

...ts/request_handler/test_request_handler_delete_stream.cpp

...er/unittests/request_handler/test_requests_dispatcher.cpp