Add TrueNAS SCALE installation guide

[HeyYuvraj]

• Added dedicated-truenas-scale.md: a step-by-step guide for installing TrueNAS SCALE on dedicated servers.
• Linked to suggestion issue: Installing TrueNAS SCALE on a VPS using a Custom ISO #1633

[cursor]

PR Summary

Low Risk
Low risk documentation-only change that adds a new guide and does not modify product code or behavior.

Overview
Adds a new dedicated-server guide docs/dedicated-truenas-scale.md covering end-to-end TrueNAS SCALE setup.

The doc walks through obtaining and mounting the ISO via iLO remote console, running the installer (including boot/EFI choices and unmounting media), setting the correct boot volume in RAID ROM, and performing initial post-install tasks like network setup, creating pools/datasets, configuring SMB/NFS sharing, and connecting from Windows.

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[fgalz]

Hey @HeyYuvraj,

I'll review the contribution submission in detail at the beginning of next week and follow up with feedback afterwards. 🙂