Add a section to allow the user to save his/her favourite skills #322

[Sangu80]

   struct landmarkList : View {
       @state var showFavoritesOnly = false

       var body : some View{
           NavigationView{
               List(landmarkData) { landmark in
                   if !self,showFavoritesOnly || landmark.isFavorite {
               NavigaitonLink(destination: LandmarkDetail(landmark: landmark))
                    Landmarkrow(landmark: landmark)

                }
           }
           .navigationBarTitle(Text("Landmarks"))
       }
   }

Fixes #[Add issue number here. If you do not solve the issue entirely, please change the message e.g. "First steps for issues #IssueNumber]

Changes: [Add here what changes were made in this issue and if possible provide links.]

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