Add various informative alert-boxes

flutter/lib/pages/sender_list/sender_list.dart

@@ -2,8 +2,10 @@ import 'package:flutter/material.dart';
 import 'package:infinite_scroll_pagination/infinite_scroll_pagination.dart';
 import 'package:provider/provider.dart';
 import 'package:simplecloudnotifier/api/api_client.dart';
+import 'package:simplecloudnotifier/components/badge_display/badge_display.dart';
 import 'package:simplecloudnotifier/components/layout/scaffold.dart';
 import 'package:simplecloudnotifier/models/sender_name_statistics.dart';
+import 'package:simplecloudnotifier/state/app_settings.dart';
 import 'package:simplecloudnotifier/state/application_log.dart';
 import 'package:simplecloudnotifier/state/app_auth.dart';
 import 'package:simplecloudnotifier/pages/sender_list/sender_list_item.dart';
@@ -69,16 +71,35 @@ class _SenderListPageState extends State<SenderListPage> {
       showShare: false,
       child: Padding(
         padding: EdgeInsets.fromLTRB(8, 4, 8, 4),
-        child: RefreshIndicator(
-          onRefresh: () => Future.sync(
-            () => _pagingController.refresh(),
-          ),
-          child: PagedListView<int, SenderNameStatistics>(
-            pagingController: _pagingController,
-            builderDelegate: PagedChildBuilderDelegate<SenderNameStatistics>(
-              itemBuilder: (context, item, index) => SenderListItem(item: item),
+        child: Column(
+          children: [
+            BadgeDisplay(
+              text: "All sender used to send messages to this account",
+              icon: null,
+              mode: BadgeMode.info,
+              textAlign: TextAlign.left,
+              closable: true,
+              extraPadding: EdgeInsets.fromLTRB(0, 0, 0, 16),
+              hidden: !AppSettings().showInfoAlerts,
             ),
-          ),
+            Expanded(
+              child: _buildList(context),
+            )
+          ],
+        ),
+      ),
+    );
+  }
+
+  Widget _buildList(BuildContext context) {
+    return RefreshIndicator(
+      onRefresh: () => Future.sync(
+        () => _pagingController.refresh(),
+      ),
+      child: PagedListView<int, SenderNameStatistics>(
+        pagingController: _pagingController,
+        builderDelegate: PagedChildBuilderDelegate<SenderNameStatistics>(
+          itemBuilder: (context, item, index) => SenderListItem(item: item),
         ),
       ),
     );