Draft: API: remove UniqueResult, lower-case at, size for ResultSet

Summary

• Remove UniqueResult
• At and Size are lower-case now (ResultSet, MultiResultSet)

src/caosdb/entity.cpp

@@ -47,6 +47,10 @@ auto Parent::SetName(const std::string &name) -> void {
   this->wrapped->set_name(name);
 }
 
+auto Parent::GetDescription() const -> const std::string & {
+  return this->wrapped->description();
+}
+
 auto Parent::SetId(const std::string &id) -> void { this->wrapped->set_id(id); }
 
 [[nodiscard]] auto Parent::GetId() const -> const std::string & {