add template for items, copy over exercise library

WorkoutsPlus/WorkoutsPlusApp.swift

@@ -12,7 +12,7 @@ import SwiftData
 struct WorkoutsPlusApp: App {
 		var sharedModelContainer: ModelContainer = {
 				let schema = Schema([
-						Item.self,
+						Exercise.self,
 				])
 				let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false)
 				
@@ -25,7 +25,7 @@ struct WorkoutsPlusApp: App {
 		
 		var body: some Scene {
 				WindowGroup {
-						ItemLibrary()
+						ContentView()
 				}
 				.modelContainer(sharedModelContainer)
 		}