Create blogpost about branch sandboxing

Author: kirilldorr

adminforth/documentation/blog/2026-06-01-branch-sandboxing-k3s/image1.png

@@ -87,3 +87,8 @@ database:
   label: Database
   permalink: /database
   description: Databases store the business data that AdminForth exposes through resources, permissions, workflows, and agent tooling.
+
+helmfile:
+  label: Helmfile
+  permalink: /helmfile
+  description: Helmfile is a declarative tool for managing multiple Helm charts, making it easier to deploy and manage complex Kubernetes applications.