Update documentation: Remove deprecated Workstation/proprietary references

Mohammed Taqiuddinrequested to merge
mtaqiudd/amdgpu-install:master into master

Syncing documentation updates from Gerrit to ReadTheDocs.

This merge request includes the following changes:

-- Remove Workstation use case references

-- Update copyright to 2025

-- Remove deprecated installation sections

-- Update secure boot instructions

-- Drop mention of legacy OpenCL

Related Gerrit change: http://gerrit-git.amd.com/c/brahma/ec/packaging/doc/+/1295835

SWDEV-570098

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