k8s admin: expose thanos through an ingress endpoint with a real certificate

and reorder the prometheus configuration to make terraform happy

Related to infra/sysadm-environment#4385 and infra/sysadm-environment#4604

/cc @teams/sysadmin

assigned to @vsellier

The change was already applied:

#  echo |  openssl s_client -showcerts -connect 192.168.50.44:443 --servername k8s-admin-thanos.internal.admin.swh.network  2>/dev/null | openssl x509 -text | grep -e Subject: -e Issuer:
        Issuer: C = US, O = Let's Encrypt, CN = R3
        Subject: CN = k8s-admin-thanos.internal.admin.swh.network

That's awesome!

approved this merge request

merged