Improve thread-factory resource creation

thread-factory resource defines optional group-name and thread-name-pattern.

When a ThreadFactoryService is created, it does not check whether these attributes are defined before using their values.
If they are not defined, the service will use "undefined" for both the group name and thread name pattern which is unhelpful.
The ThreadFactoryAdd class should check if the attributes are defined before passing them to the service.
The ThreadFactoryService will use sensible values if these 2 attributes are not defined.