Retrieving all Context components from outer nested iteration scopes #3359

The Instance Index node has a Loop Level parameter that lets you access the outer scopes of multiple levels of nested iteration. This is akin to i, j, and k index variables commonly used in nested for loops in programming.

Today, I ran into the need to access an outer nested iteration scope with the Instance Position node as well. More generally, it needs to be possible to access any component of the Context (OwnedContextImpl) by iterating from inwards to outwards and accessing the outer levels. This likely needs to involve @TrueDoctor deciding on some architectural decisions for Graphene to make this possible.