Revamp contest settings into tabs

app/views/contests/settings_offline_edit.html.slim

@@ -0,0 +1,20 @@
+= render "settings_nav"
+
+= form_with model: @contest, url: "/contests/#{@contest.id}/settings/offline" do |form|
+  .row.mt-2.mb-3
+    .col
+      - if @contest.puzzles.length <= 1
+        .form-check.form-switch
+          = form.check_box :offline_form, class: "form-check-input"
+          = form.label :offline_form
+          .form-text = t("activerecord.attributes.contest.offline_form_warning")
+          .form-text = t("activerecord.attributes.contest.offline_form_description")
+      - else
+        .form-check.form-switch
+          = form.check_box :offline_form_fake, class: "form-check-input", disabled: true
+          = form.label :offline_form
+          .form-text = t("activerecord.attributes.contest.offline_form_warning")
+          .form-text = t("activerecord.attributes.contest.offline_form_description")
+  .row.mt-4
+    .col
+      = form.submit t("helpers.buttons.update"), class: "btn btn-primary"