new CNAMEs for the Federalist sites and update the one for atf-eregs.

[davemcorwin]

This is PR 2 to facilitate decommissioning and redirects of

atf-eregs.18f.gov to redirect to regulations.atf.gov

private-eye.18f.gov to redirect to https://github.com/18F/private-eye

agile-labor-categories.18f.gov to redirect to derisking-guide.18f.gov

Here we add the Acme Challenge CNAMEs so the new CDNs can be provisioned

Remove the existing A records for the Federalist sites since downtime is acceptable

After #594 is deployed.

• [ ] This is a new public-facing site (if so, please follow the additional instructions below)
  • [ ] Provide context
  • [ ] Assign to @18F/osc for review
  • [ ] TTS Digital Council's new site review process completed
  • [ ] Update the inventory with new site information