Add Section Enabling SSH Key Authentication On Cheaha

[Premas]

Pull Request

Intent

Add clear instructions for enabling SSH key authentication on Cheaha, improving passwordless login for SSH and Open OnDemand (OOD) shell access.

Proposed Changes

Add section Enabling SSH Key Authentication On Cheaha

Changes to Section Headers

Added new section header "Enabling SSH Key Authentication on Cheaha"

Changes to Page URLs

Related or Fixed Issues

Fixes #1125

Accessibility Checklist

I have ensured all of the following for new or changed content:

• all images have appropriate alt text. Guidelines
• all images with text have sufficient contrast ratio. Checker
• all image text is transcribed or described in body text.
• all technical terms, jargon, and abbreviations are introduced before they are used.

Style Checklist

I have done all of the following:

• searched for other relevant pages and crosslinked from my content to them.
• searched for other relevant pages and crosslinked from them to my content.
• added redirects in mkdocs.yml for any moved headers or pages.
• defined new technical terms, jargon, and abbreviations in the glossary.
• searched for existing technical terms, jargon, and abbreviations in the glossary and added crosslinks to them.
• properly formatted and introduced key branding terms. List here.