Add extra nav for settings & clean header buttons

app/views/contests/settings_onsite_edit.html.slim

@@ -0,0 +1,12 @@
+= render "params_nav"
+
+= form_with model: @contest, url: "/contests/#{@contest.id}/settings/general" do |form|
+  .row.mt-2.mb-3
+    .col
+      .form-floating
+        = form.text_field :code, autocomplete: "off", class: "form-control"
+        = form.label :code, class: "required"
+        .form-text = t("activerecord.attributes.contest.code_description")
+  .row.mt-4
+    .col
+      = form.submit t("helpers.buttons.update"), class: "btn btn-primary"