✨(backend) add subrequest auth view for collaboration server

We need to improve security on the access to The collaboration server
We can use the same pattern as for media files leveraging the nginx
subrequest feature.

src/helm/env.d/dev/values.impress.yaml.gotmpl

@@ -6,6 +6,7 @@ image:
 backend:
   replicas: 1
   envVars:
+    COLLABORATION_SERVER_SECRET: my-secret
     DJANGO_CSRF_TRUSTED_ORIGINS: https://impress.127.0.0.1.nip.io,http://impress.127.0.0.1.nip.io
     DJANGO_CONFIGURATION: Feature
     DJANGO_ALLOWED_HOSTS: impress.127.0.0.1.nip.io
@@ -104,6 +105,12 @@ ingressWS:
   enabled: true
   host: impress.127.0.0.1.nip.io
 
+  annotations:
+    nginx.ingress.kubernetes.io/auth-response-headers: "Authorization, Can-Edit, User-Id"
+    nginx.ingress.kubernetes.io/auth-url: https://impress.127.0.0.1.nip.io/api/v1.0/documents/collaboration-auth/
+    nginx.ingress.kubernetes.io/enable-websocket: "true"
+    nginx.ingress.kubernetes.io/upstream-hash-by: "$request_uri"
+
 ingressAdmin:
   enabled: true
   host: impress.127.0.0.1.nip.io