more prep work for local data storage

lib/widgets/activity_card.dart

@@ -86,7 +86,29 @@ class ActivityCardState extends State<ActivityCard> {
                     },
                   ),
                   subtitle: Text(maxLines: 2, widget.activity.description),
+                  trailing: IconButton(
+                    visualDensity: VisualDensity.compact,
+                    icon: Icon(Icons.close_rounded),
+                    onPressed: () {
+                      showAdaptiveDialog(
+                        context: context,
+                        builder: (BuildContext context) => AlertDialog(
+                          title: const Text('Activity Removal'),
+                          content: const Text('Would you like to permanently remove this activity from the current session?'),
+                          actions: <Widget>[
+                            TextButton(
+                              onPressed: () => Navigator.pop(context, 'Cancel'),
+                              child: const Text('Cancel'),
                             ),
+                            TextButton(
+                              onPressed: () => Navigator.pop(context, 'OK'),
+                              child: const Text('OK'),
+                            ),
+                          ],
+                        ),
+                      );
+                    },
+                  )),
             ],
           )),
     );

lib/widgets/session_card.dart

@@ -214,6 +214,29 @@ class SessionCard extends StatelessWidget {
                       )),
                   title: Text(maxLines: 1, data.title),
                   subtitle: Text(maxLines: 1, dateFormat.format(data.date)),
+                  trailing: IconButton(
+                    visualDensity: VisualDensity.compact,
+                    icon: Icon(Icons.close_rounded),
+                    onPressed: () {
+                      showAdaptiveDialog(
+                        context: context,
+                        builder: (BuildContext context) => AlertDialog(
+                          title: const Text('Session Removal'),
+                          content: const Text('Would you like to permanently remove this session?'),
+                          actions: <Widget>[
+                            TextButton(
+                              onPressed: () => Navigator.pop(context, 'Cancel'),
+                              child: const Text('Cancel'),
+                            ),
+                            TextButton(
+                              onPressed: () => Navigator.pop(context, 'OK'),
+                              child: const Text('OK'),
+                            ),
+                          ],
+                        ),
+                      );
+                    },
+                  ),
                 ),
                 ListTile(
                   contentPadding: const EdgeInsets.fromLTRB(15, 0, 15, 15),