launcher's self-reported data should account for multiple enrollments

[RebeccaMahany]

• The logshipper should set list of munemos/org IDs on exported logs, rather than singular munemo/org IDs
• The trace exporter should set list of munemos/org IDs on exported traces, rather than singular munemo/org IDs, and be responsive to changes in munemo list
• Checkups should account for multiple enrollments (applies to all checkups -- log, doctor, and flare supported)
• metadata.json and metadata.plist should account for multiple enrollments.