Add userspace chart and docs

This allows easy creation of user namespaces with limited permissions.

certsigner.yaml

@@ -0,0 +1,39 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: certsigner
+  namespace: kube-system
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: certsigner
+  template:
+    metadata:
+      labels:
+        app: certsigner
+    spec:
+      containers:
+      - name: certsigner
+        image: python:latest
+        command: ["cat"]
+        tty: true
+        resources:
+          requests:
+            memory: 1Mi
+            cpu: 1m
+          limits:
+            memory: 100Mi
+            cpu: 100m
+        volumeMounts:
+          - mountPath: /keys
+            name: keys
+          - mountPath: /certs
+            name: certs
+      volumes:
+        - name: keys
+          secret:
+            secretName: certsigner
+        - name: certs
+          emptyDir: {}
+      restartPolicy: Always