Introduce methods to count user, public, and upcoming events to enhance CRUD functionality for events. Additionally, add a `PaginatedResponse` schema to simplify and standardize paginated API responses. These updates support improved data querying and response handling.
This commit introduces a new CRUDEvent class to manage event-related database operations, including retrieval, creation, updating, and deletion of events. It includes corresponding unit tests to ensure the correctness of these functionalities, updates event schemas for enhanced validation, and refines timezone handling for event dates and deadlines.
