fix(dashboard): Update API keys domains with new design (#7123)

**What**
- Adds new design
- Separates secret and publishable keys into two domains (re-uses the same code).
- Adds skeleton layout for loading state of details page.
- Adds toasts.

packages/admin-next/dashboard/src/components/layout/settings-layout/settings-layout.tsx

@@ -68,8 +68,12 @@ const useDeveloperRoutes = (): NavItemProps[] => {
   return useMemo(
     () => [
       {
-        label: t("apiKeyManagement.domain.apiKeys"),
-        to: "/settings/api-key-management",
+        label: t("apiKeyManagement.domain.publishable"),
+        to: "/settings/publishable-api-keys",
+      },
+      {
+        label: t("apiKeyManagement.domain.secret"),
+        to: "/settings/secret-api-keys",
       },
       {
         label: t("workflowExecutions.domain"),