Feature request: Skip download, model selection, and extra command line options to persist between MP restarts

#### Issue details
Under Simulation - Skip download, model selection, and extra command line options to persist between MP restarts

Most often these selections are used all the time - so would be really convenient if they persisted between MP restarts

#### Version
All

#### Platform
[ x ] All
[ ] AntennaTracker
[ ] Copter
[ ] Plane
[ ] Rover
[ ] Sub

#### Airframe type

#### Hardware type

#### Logs


Start by inspecting Mission Planner's Simulation settings, using the issue's screenshot and the three selections named in the request as search terms. Trace how settings are currently loaded and saved, then verify that skip download, model selection, and extra command-line options retain their values after restarting Mission Planner.

Written by the indexing model from the issue text.