Adapt welcome route

lib/models/config.dart

@@ -16,6 +16,7 @@ class Config {
   final String clientName;
   final Color splashBackgroundColor;
   final String appName;
+  final String appQuickDescription;
 
   const Config({
     @required this.apiServerName,
@@ -24,6 +25,7 @@ class Config {
     @required this.clientName,
     this.splashBackgroundColor = defaultColor,
     this.appName = "Comunic",
+    this.appQuickDescription,
   })  : assert(apiServerName != null),
         assert(apiServerUri != null),
         assert(apiServerSecure != null),