Refactor Scope Validation and OAuth Models, Update DiscoveryDocument Protocol

[vamsii777]

This pull request includes a series of refactorings and updates to enhance the OAuth implementation. The changes made in this pull request are as follows:

• Refactor scope validation in token handlers and client validator (Incorrect Scope Format in API Response: Single String Instead of Array for Multiple Scopes #11)
• Refactor OAuth models to use structs instead of classes
• Refactor OAuthResourceServer struct
• Update DiscoveryDocument protocol to make certain properties optional
• Refactor OAuthUser struct and add Address struct (Implement OpenID Connect authentication flow #14)
• Add environment parameter to UserInfoHandler constructor (Implement OpenID Connect authentication flow #14)
• Add key rotation and deletion methods to KeyManagementService (Implement OpenID Connect authentication flow #14)
• Add keyType parameter to storeKey method
• Refactor KeyManagementService protocol to support storing different types of keys
• Refactor KeyManagementService protocol to store RSA key as a string
• Refactor key management service and JWT signer service
• Refactor DiscoveryDocument and OAuthDiscoveryDocument structs (Implement OpenID Connect authentication flow #14)
• Update KeyManagementService protocol to support async/await (Enhancing Security with JWKS Integration for OAuth 2.0 and OpenID Connect #7)
• Refactor JwksHandler to use async/await (Enhancing Security with JWKS Integration for OAuth 2.0 and OpenID Connect #7)
• Update makeJWTSigner function to support async (Enhancing Security with JWKS Integration for OAuth 2.0 and OpenID Connect #7)
• Refactor token generation to use async/await
• Refactor token handlers to use async/await
• Update scopes property from [String]? to String? in AccessToken and R...

These changes aim to improve the overall codebase and maintainability of the OAuth implementation.