docs(guides): add authentication layer guide for object storage with …

[GabrielAzion]

…functions

Add comprehensive guide for implementing JWT-based authentication to control access to Object Storage buckets using Azion Functions. Includes both English and Portuguese (Brazilian) versions covering:

• Function implementation with JWT token validation
• Token extraction from Authorization headers and cookies
• Object retrieval from Object Storage after authentication
• Advanced configurations for role-based access control and rate limiting
• Testing instructions with curl examples

Related issue: EDU-4757

I've created a comprehensive guide for implementing an authentication layer for Object Storage using Functions, in both English and Portuguese.

Files created

English version:
src/content/docs/en/pages/guides/edge-storage/auth-layer-object-storage-functions/index.mdx

Portuguese version:
src/content/docs/pt-br/pages/guias/edge-storage/camada-autenticacao-object-storage-functions/index.mdx

Guide structure

The guide follows the Diátaxis framework and includes:

1. How it works - Explains the authentication flow between users, Functions, and Object Storage
2. Requirements - Lists prerequisites including Azion CLI, Node.js, and JWT secret
3. Implementation steps:
   • Create a new Function project
   • Install the jose library for JWT verification
   • Complete code example with token extraction from headers/cookies
   • Environment variable configuration
   • Deploy instructions
4. Creating an Application - How to configure the Application and Rules Engine
5. Testing - JWT token generation and curl examples
6. Advanced configurations:
   • Role-based access control
   • Rate limiting per user with KV Store
   • Object metadata for access control
7. Related resources - Links to Object Storage API, Functions overview, and JWT integration

Key features of the implementation

• JWT validation using the jose library
• Token extraction from both Authorization header and cookies
• Object retrieval using the azion:storage API
• Proper error handling with appropriate HTTP status codes
• Security best practices (secrets management via azion secrets put)
• Extensible architecture for RBAC and rate limiting