MX records changes

I've cleaned up the osgeo.org DNS zone so we we now have only 2 MX
records, as the only one needed due to web and mail services for
those hostnames are listening on different iPs:

  - osgeo.org
  - discourse.osgeo.org

The records are now managed via ansible [1] and found in this file:

  deployment/roles/dns-records/tasks/mx.yml

They can be deployed with this command:

  ansible-playbook deployment/deploy-dns-records.yml --tags mx

Optionally, you can add the --check switch to only see if deploying
would change something (although you cannot easily see WHAT, due to
a limitation of the cloudflare ansible plugin [2]):

  ansible-playbook deployment/deploy-dns-records.yml --tags mx --check

[1] Making sure you're not a bot!
    (you need to be SAC to read)
[2] Cloudflare DNS diff mode · Issue #10797 · ansible-collections/community.general · GitHub

--strk;

  Libre GIS consultant/developer :trumpet:
  strk's services