Add SSO Catalog instructions HTML document

- Created a new HTML file for the SSO Catalog instructions.
- Included styles for markdown rendering and syntax highlighting.
- Document outlines the Identity Provider (IdP) interfaces and Relying Party (RP) integration guide.
- Covers OAuth 2.0 Authorization Code flow and Device Flow with detailed examples and error handling.
- Provides architecture diagrams and a checklist for RP registration and runtime considerations.