logging PARAM_VALUE after ftp param download

One of the things we lose with a ftp param download is the ability to easily get the full param list from a tlog. For mavproxy I've added code so that on completion of a ftp param download it adds all the params as PARAM_VALUE records in the tlog. It does it with:
- sysid = vehicles sysid
- compid = MAV_COMP_ID_MISSIONPLANNER

that associates it with the vehicle, while also showing it came from the GCS as a component.
Could you do the same in MissionPlanner?

Locate the FTP parameter-download completion path and the code that writes PARAM_VALUE records to tlogs. Compare the requested sysid, compid, and parameter-list behavior with the existing logging flow; done means a completed Mission Planner FTP parameter download produces PARAM_VALUE records associated with the vehicle and GCS component.

Written by the indexing model from the issue text.