RS: Add decision graph for maintenance mode guidance

[mich-elle-luna]

Added a decision graph section to guide users on maintenance mode usage.

[github-actions]

DOC-123456

[github-actions]

Staging links:
https://redis.io/docs/staging/DOC-123456/operate/rs/clusters/maintenance-mode/

[github-actions]

🧠 Redis Repository Memory

Found 5 related items from repository history:

• Commit — RS: Add decision graph for maintenance mode guidance

  RS: Add decision graph for maintenance mode guidance

• PR — DOC-6026 page about when to use RDI

  The content for this is mainly taken from the existing RDI landing page, with a few small changes. The decision tree renders as a diagram in

• PR — RS: Rearranged upgrade Active-Active DB page and added more details about rladmin status output
• PR — DOC-6128 RDI: reduce negative tone of "When to use/not use" decision tree

  I've added an "indeterminate" option to the decision tree outcomes (so we now have Red-Amber-Green rather than just Red-Green). I've used th

• PR — RS: Added OPS monitoring dashboards

Memory updated at 80f1c0b