Through the changes in the new servo architecture, we can do the following

(1) after the initial phase of figuring out the 'real' options i.e. bootstrapping, figuring out prefixes, board, model, serialnames, etc, we can generate a synthetic and unique cmdline for a given instance.

(2) stash that cmdline in the servo scratch

(3) for restart first kill the old instance, then invoke a new servod with that cmdline. It won't prompt for any user input as it's already not ambigious and should start the instance again

This bug is to keep track of that effort, leave the action item behind