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

Summary

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

include/caosdb/entity.h

@@ -442,7 +442,7 @@ public:
 
   auto SetRole(const std::string &role) -> void;
   auto SetName(const std::string &name) -> void;
-
+  auto SetDescription(const std::string &description) -> void;
   auto SetValue(const std::string &value) -> void;
   auto SetUnit(const std::string &unit) -> void;
   // Currently no references or lists.