feat: poder crear sitios en testing

los sitios en testing no se sincronizan con otros servidores y siempre
son locales al panel

app/views/sites/_form.haml

@@ -23,7 +23,7 @@
       = f.text_field :name,
         class: form_control(site, :name),
         required: true,
-        pattern: '^([a-z0-9][a-z0-9\-]*)?[a-z0-9\.]$',
+        pattern: '^([a-z0-9][a-z0-9\-]*)?[a-z0-9\.](\.testing)?$',
         minlength: 1,
         maxlength: 63
       - if invalid? site, :name