Add pagination classes and extensions

[sunecko]

Add PaginatedRequest and PaginatedResponse classes to handle data pagination in the API. Also include the ToPaginatedResult extension for paginating data collections. These additions facilitate the implementation of pagination in API responses.

public class ExampleRequest: PaginatedRequest
{
    public string Name { get; set; } = string.Empty;
}

public class ExampleResponse
{
    public string Message { get; set; } = string.Empty;
}

public class ExampleEndpoint: Endpoint<ExampleRequest, PaginatedResponse<ExampleResponse>>
{
    public override void Configure()
    {
        Get("/example");
        AllowAnonymous();
    }

    public override async Task HandleAsync(ExampleRequest req, CancellationToken ct)
    {
        var data = new List<ExampleResponse>
        {
            new ExampleResponse { Message = "Hello Fast Endpoints" },
            new ExampleResponse { Message = "Hello BrodSquad" },
        };

        await SendOkAsync(data.ToPaginatedResult(req.PageNumber, req.PageSize));
    }
}

[CerealKiller97]

@hectorrhg Thanks for the contribution 🎉.