[cmd3] Improve Trigger telemetry

[SamCarlberg]

• Update ScheduledEvent to include the trigger that the scheduled command was bound to. Null for commands scheduled manually. This may require updating Binding to hold a reference to the trigger
• Add a name field to Trigger. This could be passed as a constructor parameter or changed later with a .setName(String) method. If no name is specified in the constructor, generate and assign a unique name
• Update scheduler protobuf telemetry:
  • Add an optional string triggered_by field to the ProtobufCommand message
    • Set this to the name of the trigger that caused the command to be scheduled
    • Leave empty if the command was not scheduled by a trigger
• Update the design doc to account for the changes made