Update Documentation for MTC on Pathways

[SujeethJinesh]

Description

Update MTC documentation to include Pathways workload deployment documentation using Cluster Toolkit.

FIXES: b/488344921

Tests

N/A - only documentation. Verified md and sphinx formatting.

Checklist

Before submitting this PR, please make sure (put X in square brackets):

• I have performed a self-review of my code. For an optional AI review, add the gemini-review label.
• I have necessary comments in my code, particularly in hard-to-understand areas.
• I have run end-to-end tests tests and provided workload links above if applicable.
• I have made or will make corresponding changes to the doc if needed, including adding new documentation pages to the relevant Table of Contents (toctree directive) as explained in our documentation.

[gemini-code-assist]

Caution

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