Register activities with DI and allow the lifetime to be defined

[sclarke81]

I've been talking to @WhitWaldo on Discord about being able to use activities with a scoped lifetime. The root of this for me was a library I'm using is trying to get the HttpContext using IHttpContextAccessor and the context is null.

This led to this PR: #1408

However, I think for this change to work fully I think we'd have to change the way activities are registered. Currently it's adding an activity to the durable task registry using a factory function. The function we pass in calls ActivatorUtilities.CreateInstance to create the instance of the activity. It looks like the factory is used so that the activity can be wrapped with the ActivityWrapper. I think instead the activity could be registered with DI with the correct scope and then use ActivatorUtilities.GetService in the factory. It'd mean passing the scope into the WorkflowRuntimeOptions as well.

I'm not sure if there would be any repercussions to doing this.

[WhitWaldo]

We don't have a milestone for v1.16 yet, so I've tagged this Future for now, but I'll revisit when that changes after the 1.15 release.