Add Recursive RoleSet identifier to all cache nodes

[TTWNO]

Thanks to my professor, Dr. Robert Benkoczi, for suggesting this idea.

This adds a recursive RoleSet to all nodes, which tells you what roles itself or its children have.

• This increases insertion time from O(1) to O(k+c) where k is the number of ancestors of a given node, and c is the number of children.
• This increases deletion time from O(1) to O(k+s) where k is the number of ancestors of a given node, an s is the total number of all siblings in k.
• In both the above cases, the constant factor is very low (RoleSet is simply 134 bits and and ored to get results)
• This decreases average time taken for structural navigation (find next node with role "X"), but technically in a very unbalanced or skewed tree it could still take O(n) time (but, due to the comparative shallowness and balance of the accessibility tree, it is generally much faster).

TODO

• Structural navigation benchmark (modify existing traversal benchmark)
  • test on main and this branch
• Convert existing JSON struct to one with valid RoleSets
• Consider possibility of adding likewise: AttributeSet or StateSet for all nodes as well (even if just for limited structural navigation reasons like unvisited links or checked boxes)
• See if something like this could be a bit more generic (this interface currently requires a lot of manual updating logic)