add always sorted [WorkoutItem], ContentUnavailableView to searches, SampleData import, refactor WorkoutItem init

WorkoutsPlus/Exercise/ExerciseLibrary.swift

@@ -37,6 +37,7 @@ struct ExerciseLibrary: View {
 												ExerciseDetail(exercise: exercise)
 										} label: {
 												Text(exercise.name)
+												// TODO: show exercise.metric in gray (eg Dips = reps, Intervall = time or = distance?)
 										}
 								}
 								.onDelete(perform: deleteExercise)
@@ -49,15 +50,24 @@ struct ExerciseLibrary: View {
 										.textInputAutocapitalization(.words)
 										.focused($isInputFieldFocused)
 								}
+								if filteredItems.isEmpty {
+										ContentUnavailableView.search(text: searchText)
+								}
 								AddItemButton(label: "Exercise", action: addExercise)
 						}
 						.searchable(text: $searchText)
+						
 				}
 				.navigationTitle("Exercises")
 				.toolbar {
 						ToolbarItem {
 								EditButton()
 						}
+						ToolbarItem {
+								Button(action: {}) {
+										Image(systemName: "plus")
+								}
+						}
 				}
 		}