F update

Summary

Implements update for a single entity

See https://gitlab.indiscale.com/caosdb/customers/lfpb/management/-/issues/392

Focus

• Updating entities works like this: Retrieve an entity, copy it and put it in the update transaction.
• ResultSet has an iterator now
• I privatated SetId and SetVersionId (nobody should ever need to change it, because Entities which are to be updated have to be retrieved first anyway.)
• More fine-grained TransactionStatus (INITIAL -> GO_ON -> READY -> EXECUTE -> SUCCESS/ERROR) and corresponding StatusCodes

Test Environment

Use with server branch f-grpc-f-update

Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a focus and create gitlab comments for the reviewer. They should guide the reviewer through the changes, explain your changes and also point out open questions. For further good practices have a look at our review guidelines

• All automated tests pass
• Reference related Issues
• Up-to-date CHANGELOG.md
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there specifications? Are they satisfied?

For further good practices have a look at our review guidelines.

src/caosdb/transaction.cpp

@@ -104,7 +104,10 @@ ResultSet::iterator::iterator(const ResultSet *result_set_param, size_t index)
   : current_index(index), result_set(result_set_param) {}
 
 auto ResultSet::iterator::operator*() const -> const Entity & {
-  return this->result_set->At(current_index);
+  // TODO(tf) clang warns about a bugprone conversion from unsigned
+  // size_t to signed int, i.e., the `index` of ResultSet::At. Should
+  // we make this unsigned as well?
+  return this->result_set->At(current_index); // NOLINT
 }
 
 auto ResultSet::iterator::operator++() -> ResultSet::iterator & {