Configure K8s deployment for easy LetsEncrypt verification.

This is not the certificate setup we will use in production. I'd like to
merge this configuration as a reference point because this is the
easiest way to handle manual LetsEncrypt verification within the
cluster.

This allows NGINX to serve static files over HTTP from the
".well-known/acme-challenge" directory, which is necessary for certbot
validation of domain ownership.

deploy/azure/kustomization.yaml

@@ -9,3 +9,4 @@ resources:
   - pgsslrootcert.yml
   - volume-claim.yml
   - nginx-client-ca-bundle.yml
+  - acme-challenges.yml