[improvement] Patched ingress-gce

[atb00ker]

ingress-gce: doesn't let ingress work if it has tls and no certificates. So I had to add a patch information in documentation:

kubectl patch ingress/openwisp-http-ingress \
    --patch '{
        "spec": {
            "tls": [
                {
                "hosts": [
                    "dasboard.openwisp.org",
                    "controller.openwisp.org",
                    "radius.openwisp.org",
                    "topology.openwisp.org"
                ],
                "secretName": "openwisp-tls-secret"
                }
            ]
        }
    }'

This may not be required in future versions of cert-manager.

Blocked: https://github.com/jetstack/cert-manager/issues/606#issuecomment-424401686 :smile:

[atb00ker]

P.S: Useful link https://cert-manager.io/docs/usage/ingress/ (These annotations may solve the problem.)