Save terminals upon exiting app

[aahlrichs5]

Now that we can give terminals custom icons/colors/names let us save those terminals so that when we exit the app they are still there. It would be nice to not have to set these up every time I restarted the app.

[meganrogge]

You can create custom terminal profiles, which make it very easy to recreate the terminals when re-opening VS code.

If you mean you want the terminals to persist upon re-opening the window, that would likely be a by-product of implementing #10121