[ACME] Skip mta-sts certificate request when MTA-STS is not active for a domain

data/web/lang/lang.en-gb.json

@@ -728,6 +728,7 @@
         "mta_sts_mx": "MX server",
         "mta_sts_mx_info": "Allows sending only to explicitly listed mail server hostnames; the sending MTA checks if the DNS MX hostname matches the policy list, and only allows delivery with a valid TLS certificate (guards against MITM).",
         "mta_sts_mx_notice": "Multiple MX servers can be specified (separated by commas).",
+        "mta_sts_active_info": "If unchecked, the MTA-STS policy will not be published and no certificate will be requested for the mta-sts subdomain via ACME.",
         "multiple_bookings": "Multiple bookings",
         "none_inherit": "None / Inherit",
         "nexthop": "Next hop",