[acs-wg] CDDLM sequence

Hi Keisuke and all, I updated the collaboration sequence diagrams in accordance with the ACS glossary Keisuke posted earlier. Keisuke, could you use this one if you ask CDDLM team to review? I also added some explanation about the actors in the diagram, but it may be redundant especially for CDDLM team since the most part of the explanation is about CDDLM services. Sachiko