Changes

• Change to use the compose multi-platform view model
• Moved ViewModelBackStackRecordLocalProvider into circuit foundation out of backstack
  • Think it makes more sense for this to exist within foundation?
  • Allows for using circuit retained instead of fishing for an Activity
• Provide the ViewModelBackStackRecordLocalProvider as default on the circuit instance instead of as a static val
  • Now allows for setting default BackStackRecordLocalProvider's
• Add backStackHostViewModel() to allow access to a ViewModel in the host of the NavigableCircuitContent