Add support for server conversation message

lib/ui/tiles/server_conversation_message_tile.dart

@@ -0,0 +1,33 @@
+import 'package:comunic/lists/users_list.dart';
+import 'package:comunic/models/conversation_message.dart';
+import 'package:flutter/material.dart';
+
+/// Server conversation message list
+///
+/// @author Pierre hubert
+
+class ServerConversationMessageTile extends StatelessWidget {
+  final ConversationServerMessage message;
+  final UsersList users;
+
+  const ServerConversationMessageTile({
+    Key key,
+    @required this.message,
+    @required this.users,
+  })  : assert(message != null),
+        assert(users != null),
+        super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: Text(
+        message.getText(users),
+        style: TextStyle(
+          fontStyle: FontStyle.italic,
+          fontSize: 12,
+        ),
+      ),
+    );
+  }
+}