Migration support and DNS improvements

1.5.0

Some elected changelog items

DNS improvements

• fix checking for required DNS records
  (#412)

• query autoritative nameserver to bypass DNS cache
  (#424)

Migration support

• add guide to migrate chatmail to a new server
  (#429)

• add cmdeploy run --disable-mail to disable postfix/dovecot for migration
  (#428)

• add argument to cmdeploy run for specifying
  a different SSH host than mail_domain
  (#439)

Operations

• add support for specifying whole domains for recipient passthrough list
  (#408)

• trigger "apt upgrade" during "cmdeploy run"
  (#398)

• drop hispanilandia passthrough address, as it stopped service
  (#401)

Monitoring

• add mtail support (new optional mtail_address ini value)
  This defines the address on which mtail
  exposes its metrics collected from the logs.
  If you want to collect the metrics with Prometheus,
  setup a private network (e.g. WireGuard interface)
  and assign an IP address from this network to the host.
  If you do not plan to collect metrics,
  keep this setting unset.
  (#388)