Add RESTful Dubbo Integration with Spring Security and OAuth2 Sample

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This pull request introduces a sample project that demonstrates how to integrate Dubbo with RESTful APIs, incorporating Spring Security and OAuth2 for authentication and authorization. The sample showcases the following key functionalities:

1. Dubbo RESTful Integration:

• A RESTful API is exposed for Dubbo services, enabling easier interaction with external systems.

2. Spring Security Setup:

• Spring Security is configured to secure the endpoints, ensuring that only authorized users can access the Dubbo services via the REST API.

3. OAuth2 Authentication:

• OAuth2 authentication is implemented to handle secure access to the resources, with token validation for API access.

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