doc/start: remove L and N release-related tables

[zdover23]

This PR removes the tables for Luminous and Nautilus,
in order to keep the documentation as current as possible.
This is one in a series of PRs intended to update the OS
Recommendations page. The scope of this PR is confined to
the removal of these two tables. Other PRs will update the
information elsewhere on the OS Recommendations page.

Signed-off-by: Zac Dover zac.dover@gmail.com

Checklist

• Tracker (select at least one)
  • References tracker ticket
  • Very recent bug; references commit where it was introduced
  • New feature (ticket optional)
  • Doc update (no ticket needed)
  • Code cleanup (no ticket needed)
• Component impact
  • Affects Dashboard, opened tracker ticket
  • Affects Orchestrator, opened tracker ticket
  • No impact that needs to be tracked
• Documentation (select at least one)
  • Updates relevant documentation
  • No doc update is appropriate
• Tests (select at least one)
  • Includes unit test(s)
  • Includes integration test(s)
  • Includes bug reproducer
  • No tests

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