DX - 1237 - Adding OAuth Support

[cs-raj]

version bump: 0.3.2 -> 0.4.0

Core Classes

• OAuthHandler: Main class for OAuth operations and flow management
• OAuthOptions: Configuration options for OAuth setup
• OAuthTokens: Token storage and management with validation
• PkceHelper: PKCE code generation and validation utilities
• OAuthTokenService: HTTP service for token exchange and refresh

Service Layer

• OAuthAppAuthorizationService: Handles app authorization requests
• OAuthAppRevocationService: Manages app revocation functionality
• OAuthTokenService: Core token management operations
• Thread-safe token storage using Dictionary<string, OAuthTokens>
• HTTP pipeline integration with automatic Bearer token injection

[nadeem-cs]

LGTM!