[DOCS] Reorganize documentation structure

[adriangalilea]

Summary

• Reorganized documentation file structure for improved navigation
• Standardized file naming conventions and removed duplicative content (ex: merged Home.md & Markdown-Oxide.md -> index.md)
• Fixed references between files to maintain proper linking
• Made overall structure more logical with key documents in root and better categorization

Closes #249

@Feel-ix-343 review tasks

• Navigate to https://oxide.md and verify all links work correctly
• Check that content flows logically from main pages to detailed reference docs
• Verify no broken links or formatting issues
• Sort out files under /rug as explained on it's README.md

Note: The GIF-to-text conversion part of issue #249 is left for @Feel-ix-343 to address as noted in the original issue.