Remove bootstrap_upgrade_notes: obsolete Puppet Server 2.4→2.5 migration guide

The page documented upgrade precautions for Puppet Server 2.4.x to 2.5.0
(circa 2015–2016), which is not a relevant upgrade path for OpenVox 8.x users.
Remove the page, its nav entry, and the reference note in configuration.markdown.

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

@@ -43,8 +43,6 @@
     link: puppet_conf_setting_diffs.html
   - text: 'Configuring product-level interactions (optional): product.conf'
     link: config_file_product.html
-  - text: Bootstrap upgrade notes
-    link: bootstrap_upgrade_notes.html
 - text: Using and extending OpenVox Server
   items:
   - text: Using Ruby gems

docs/_openvox-server_8x/bootstrap_upgrade_notes.markdown

@@ -128,8 +128,6 @@ Any files with a `.cfg` extension in either of these locations are combined to f
 The CA-related configuration settings are set in `/etc/puppetlabs/puppetserver/services.d/ca.cfg`. If services added in future versions have user-configurable settings, the configuration files will also be in
 this directory. When upgrading Puppet Server 2.5.0 and newer with a package manager, it should not overwrite files already in this directory.
 
-> **Note:** If you're upgrading from Puppet Server 2.4.x or earlier to Server 2.5 or newer, read and act on the [bootstrap upgrade notes](./bootstrap_upgrade_notes.html) **before upgrading**.
-
 In the `ca.cfg` file, find and modify these lines as directed to enable or disable the service:
 
 ```text