Added deep links for widgets

- Widgets will now open the appropriate DetailView in the app when you tap on them.
  - ...except when they don't. This is still a little buggy. It works correctly when the app is already alive in the background but only works about 75% of the time when the app isn't running yet.
- Unified the loading view into a shared view used in all places requiring loading

TigerDine/Views/LocationList.swift

@@ -57,7 +57,7 @@ struct LocationList: View {
     
     var body: some View {
         ForEach(filteredLocations, id: \.self) { location in
-            NavigationLink(destination: DetailView(locationId: location.id)) {
+            NavigationLink(value: location) {
                 VStack(alignment: .leading) {
                     HStack {
                         Text(location.name)