doc/start/os-recommendations: update for Umbrella and future releases

doc/start/os-recommendations: update for Umbrella and future releases

Overhaul the OS recommendations documentation to reflect deployment
practices and map out the support matrices for upcoming releases through
Ceph X (24.x).

Key changes include:

* Emphasized container-based deployments: Added a new section strongly
  recommending containerized deployments via `cephadm` over legacy
  package-based installations to simplify upgrades and avoid host-level
  dependency conflicts.
* Expanded support tables: Updated the Platforms and Container Hosts
  tables to include Umbrella (21.x), Vampire (22.x), W (23.x), and
  X (24.x). Removed EOL releases like Reef.
* Added EOL visibility: Included End-of-Life dates for Linux
  distributions and anticipated EOL dates for Ceph releases to help
  administrators plan lifecycle events.
* Updated OS targets: Added support tracking for Ubuntu 24.04 (Noble),
  Ubuntu 26.04, Ubuntu 28.04, Rocky Linux 10, and Rocky Linux 11.
* Addressed CentOS transition: Added a warning that CentOS 10+ will no
  longer be built or tested by upstream. Documented that Rocky Linux 10
  is the new default container base image for Umbrella, while clarifying
  that the bare-metal host OS can remain any supported distribution.
* Added horizontal upgrade guidance: Introduced a new section outlining
  safe "horizontal" bare-metal OS upgrade paths (e.g., CentOS 9 to
  Rocky 10, Ubuntu 22.04 to 24.04) so users can safely migrate their
  nodes outside of Ceph version upgrade windows.

AI-Assisted: Gemini Pro, through numerous prompts
Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>