Generic cookies

[YuriyDurov]

Allows setting and retrieving generic cookies, automatically serializing and deserializing their respective values as needed. E.g.

public class MyClass
{
    public int MyValue { get; set; }
}

// new Cookie<T> class usage examples
public void ExampleCookieUsage()
{
    var data = new MyClass
    {
        MyValue = 1
    };

    var cookie = Cookie.FromValue("key", data);
    // or
    var cookie = new Cookie<MyClass>("key", data);
    // or
    var stringValue = JsonSerializer.Serialize(data);
    var cookie = new Cookie("key", stringValue).Cast<MyData>();

    // this cookie can then be persisted using ICookieService
}

// New method allows for automatic value deserialization when retrieving a cookie
public void ExampleServiceUsage(ICookieService cookieService)
{
    Cookie<MyData> myCookie = cookieService.Get<MyData>("key");
}