tf-stage1: standardize on TTL 3600 for DNS records

Almost all of our DNS records have a TTL of 86400 (24 hours) with a few using a TTL of 600 (some MX and TXT records). The former is too long to be flexible when a need for fast change(s) arises, and the latter don't benefit from the low TTL. Standardize on a TTL of 3600 (1 hour) for all our records.

tf-stage1/archlinux.tf

@@ -310,7 +310,7 @@ locals {
     "_mta-sts.lists"      = { value = "_mta-sts" }
   }
 
-  # This creates pkgbuild.comA/AAAA DNS entries in addition to those already specified by the VPSes.
+  # This creates pkgbuild.com A/AAAA DNS entries in addition to those already specified by the VPSes.
   # The VPSes already get a default domain assigned based on their domain parameter.
   # Thus the domains in local.pkgbuild_com_a_aaaa are additional domains or domains assigned to dedicated servers.
   #