Add friend tab

lib/ui/screens/friends_list_screen.dart

@@ -20,6 +20,10 @@ import 'package:flutter/material.dart';
 enum _ErrorsLevel { NONE, MINOR, MAJOR }
 
 class FriendsListScreen extends StatefulWidget {
+  final bool showAppBar;
+
+  const FriendsListScreen({Key key, this.showAppBar = true}) : super(key: key);
+
   @override
   State<StatefulWidget> createState() => _FriendsListScreenState();
 }
@@ -103,9 +107,11 @@ class _FriendsListScreenState extends SafeState<FriendsListScreen> {
 
   @override
   Widget build(BuildContext context) => Scaffold(
-        appBar: AppBar(
-          title: Text(tr("Your friends list")),
-        ),
+        appBar: widget.showAppBar
+            ? AppBar(
+                title: Text(tr("Your friends list")),
+              )
+            : null,
         body: _buildBody(),
       );