quick resolve for https://github.com/micromdm/micromdm/issues/580
this just ensures that each time a command is moved to completed it's time is recorded in the struct. useful to prune completed commands by date.
Previously the github.com/micromdm/mdm library was used, but the code there was a bit naive and had a few issues as it grew to support the full library of MDM Commands.
All the request types have been moved to `package mdm`.
Add more logic to the way code is organized.
/pkg -- library code not directly connected to micromdm
/mdm -- packages meant for the services devices interract with. The MDM protocol.
/dep -- DEP API and related packages.
/platform -- Core APIs the server provides. Commands API, Devices API, queue, pubsub etc.
/workflow -- Packages/API that build on top of platform. Today that's the webhook package.
Depending on what ends up here, the workflow folder might become its own repository.
