Merge branch 'f-async-execute' into 'dev'

conanfile.py

doc/CHANGELOG.md

include/caosdb/authentication.h

include/caosdb/file_transmission/download_request_handler.h

...e/caosdb/file_transmission/register_file_upload_handler.h

include/caosdb/file_transmission/upload_request_handler.h

include/caosdb/logging.h

include/caosdb/transaction.h

include/caosdb/transaction_handler.h

include/caosdb/transaction_status.h

include/caosdb/unary_rpc_handler.h

src/caosdb/authentication.cpp

src/caosdb/connection.cpp

src/caosdb/file_transmission/download_request_handler.cpp

...caosdb/file_transmission/register_file_upload_handler.cpp

src/caosdb/file_transmission/upload_request_handler.cpp

src/caosdb/logging.cpp

src/caosdb/transaction.cpp

src/caosdb/transaction_handler.cpp

src/caosdb/unary_rpc_handler.cpp