[doc] Manage supported platforms in a single place

With changing list of supported platforms, it's easy to forget where
exactly they are defined, and miss mentioning them for a while.

Usage of the raw include should ease the process. RST import
was not used to prevent possible issues with doubling translations.

Change-Id: Ia8fe370b660ee6a7c4277cb1f0428c81cbdbfa6a

deploy-guide/source/deploymenthost.rst

@@ -26,8 +26,8 @@ Install the operating system
 Install one of the following supported operating systems on the deployment
 hosts:
 
-* `Ubuntu server 24.04 (Noble Numbat) LTS 64-bit <http://releases.ubuntu.com/24.04/>`_
-* `Debian 12 (Bookworm) LTS 64-bit <https://www.debian.org/distrib/>`_
+.. raw:: HTML
+    :file: supported-platforms.html
 
 Configure at least one network interface to access the Internet or suitable
 local repositories.

deploy-guide/source/overview-requirements.rst

@@ -4,13 +4,12 @@ Software requirements
 Ensure that all hosts within the OpenStack-Ansible (OSA) environment meet the
 following minimum requirements:
 
-* Debian
+Operating Systems:
 
-  * Debian 12 (bookworm)
+.. raw:: HTML
+    :file: supported-platforms.html
 
-* Ubuntu
-
-  * Ubuntu 24.04 LTS (Noble Numbat)
+Configuration:
 
 * Secure Shell (SSH) client and server that support public key
   authentication

deploy-guide/source/supported-platforms.html

@@ -0,0 +1,4 @@
+<ul>
+  <li>Ubuntu Server 24.04 (Noble Numbat) 64-bit</li>
+  <li>Debian 12 64-bit</li>
+</ul>

deploy-guide/source/targethosts-prepare.rst

@@ -11,8 +11,9 @@ Installing the operating system
 Install one of the following supported operating systems on the
 target host:
 
-* Ubuntu server 24.04 (Noble Numbat) LTS 64-bit
-* Debian 12 64-bit
+.. raw:: HTML
+    :file: supported-platforms.html
+
 
 Configure at least one network interface to access the Internet or
 suitable local repositories.