remove mentions of deprecated Nomad versions in docs

[sofixa]

Description

A few docs had mentions such as "Starting Nomad x.x" where x.x are long since out of support, or contained obsolete upgrade guidance (e.g. to Raft version 3).

Contributor Checklist

• Documentation If the change impacts user-facing functionality such as the CLI, API, UI,
  and job configuration, please update the Nomad website documentation to reflect this. Refer to
  the website README for docs guidelines. Please also consider whether the
  change requires notes within the upgrade guide.

Reviewer Checklist

• Backport Labels Please add the correct backport labels as described by the internal
  backporting document.
• Commit Type Ensure the correct merge method is selected which should be "squash and merge"
  in the majority of situations. The main exceptions are long-lived feature branches or merges where
  history should be preserved.
• Enterprise PRs If this is an enterprise only PR, please add any required changelog entry
  within the public repository.
• Review that the deprecated configs/features for which the docs were removed have the corresponding code removed (e.g. client options for plugin config, or port_map for port mapping).

[aimeeu]

Are these fingerprinting parameters related to drivers? I thought the client agent does the fingerprinting.

[tgross]

These are still deprecated, but they have not been removed. We should not remove this section, as some of the values don't have replacements yet. See #12420