WIP: insert delete

.gitlab-ci.yml

include/CMakeLists.txt

include/caosdb/entity.h

include/caosdb/exceptions.h

include/caosdb/protobuf_helper.h

include/caosdb/status_code.h

include/caosdb/transaction.h

proto

src/CMakeLists.txt

src/caosdb/entity.cpp

src/caosdb/protobuf_helper.cpp

src/caosdb/transaction.cpp

test/CMakeLists.txt

test/test_entity.cpp

test/test_protobuf.cpp

test/test_transaction.cpp