Add support for passthrough workflow setting

[Christoffer Winterkvist]

We should consider adding support for a workflow keyboard shortcut binding annotated with passthrough. Which would mean that the workflow binding would still pass the command to the system untouched. But the workflow would run alongside the system keyboard shortcut.

It think that could be useful to really take workflows to the next level.

[Christoffer Winterkvist]

We probably need to introduce an extra layer.
Something like this might work:

struct KeyboardShortcutTrigger {
  var passthrough: Bool
  let shortcuts: [KeyShortcut]
}

Then we need to provide a custom decoder in order to preserve previous configurations. Should be fairly straight forward to migrate.