GEMS17 — Clarify use cases and association with implementations

During the March 23, 2022 GEMS RTF Meeting, the RTF members agreed to:
1. Add diagrams to sections 6.2.8 (Save Configuration Message), 6.2.9 (Restore Configuration Message), 6.2.11 (Asynchronous Status Message), and possibly 6.2.10 (get device definition file) for consistency with prior sections.
2. Add references from the PIM and PSM sections back to the use cases.