Binding Editor graph location is shared across all bindings

[jdaignault]

Given a widget that has multiple bindings authored, it appears that the graph location is globally shared while switching view between the different binding instances. This can cause some minor UX annoyance if the locations of all binding nodes are not uniform across every binding instance.

Steps to reproduce:

1. Create a widget with two bindings
2. In the first binding, add a Read a Property node at the top-left corner of the viewport
3. In the second binding, add a Read a Property node at the bottom-right corner of the viewport
4. Return to the first binding, and pan the viewport up and left until the node is located at the bottom-right corner of the viewport
5. Switch back to the second binding, and observe that the node is nowhere in sight. The user must zoom out and pan around to find it

It would be nice if the graph location was independent per-binding, and/or if there was a way to automatically frame the nodes towards the center of the viewport.