Refactor RPC Provider Configuration to Support Multiple Services

[evandrosaturnino]

The PR #785 introduces an implementation which is tightly coupled to Alchemy, making it difficult to integrate alternative RPC providers. To improve flexibility and future-proof the code, introduce a generic configuration structure. For example, use an API_SERVICE_NAME and API_KEY along with a mapping of service names to their respective configurations. This will allow adding or switching RPC providers by simply updating the mapping rather than modifying core logic.