ISessionStore.Create() should also receive the HttpContext

In ASP.NET, if you want to manage session cookies yourself, you must use implement the `ISessionStore` interface. This interface contains a single method called `Create()` that basically serves as the "factory" for each request's `ISession` object. The `Create()` method is called on every request if you have the `app.UseSession()` line in `Program.cs`.

Currently, the signature for `ISessionStore.Create` is the following:

```c#
ISession Create(string sessionKey, TimeSpan idleTimeout, TimeSpan ioTimeout, Func tryEstablishSession, bool isNewSessionKey);
```

As you can see, although `Create()` is called on every request, there is no `HttpContext` object passed to it. For my particular setup, I need a few things from the `HttpContext` object when creating the `ISession` object. Right now, in order to get access to the current `HttpContext` object in the `Create()` method, I have to pass in a `IHttpContextAccessor` to the `ISessionStore` so that I can get it that way. I feel this is overkill for something that could be easily added as a parameter to `Create()`.

I've noticed that ASP.NET does a pretty good job of making an `HttpContext` object available anywhere a method runs in the context of a request, however this is one place that I think it was overlooked.

My proposal is the following: Add an `HttpContext` parameter to the end of the existing parameters to `Create()`, like this:

```c#
ISession Create(string sessionKey, TimeSpan idleTimeout, TimeSpan ioTimeout, Func tryEstablishSession, bool isNewSessionKey, HttpContext context);
```