Remove obsolete auth.conf migration guide

This page documented the migration from the legacy Puppet auth.conf
format to HOCON, introduced in Puppet Server 2.2.0 (2015). The old
format was removed entirely in Puppet Server 7. No OpenVox 8.x user
needs this guide. Removes the page and its nav entry.

Signed-off-by: Michael Harp <mike@mikeharp.com>
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Michael Harp <mike@mikeharp.com>

Author: miharp

_data/nav/openvox-server_8x.yml

@@ -68,8 +68,6 @@
     link: tuning_guide.html
   - text: Scaling OpenVox Server with compilers
     link: scaling_puppet_server.html
-  - text: Migrating to the HOCON auth.conf format
-    link: config_file_auth_migration.html
 - text: Administrative API endpoints
   items:
   - text: Environment cache