Multiple domains in issuer certificate

Addresses the payments.private.storage TLS certificate part of https://whetstone.privatestorage.io/privatestorage/privatestorageops/-/issues/333

Currently deployed on staging:

$ openssl s_client -connect payments.privatestorage-staging.com:443 2>/dev/null </dev/null | grep -A 31 'BEGIN CERTIFICATE'  | openssl x509 -noout -text | grep -i -A1 alt
            X509v3 Subject Alternative Name: 
                DNS:payments.extra.privatestorage-staging.com, DNS:payments.privatestorage-staging.com

Failed on CI because the CI runner has been tainted by VirtualBox which makes it incapable of running things with KVM. After cleaning VirtualBox off my laptop I was able to run the system tests locally (where they passed).

merged

mentioned in commit 5ba31506