Add a curve editor to the Inspector

[thomlucc]

Add a curve editor to the Inspector in the same way the particle editor was recently added.

The goal of the animation curve editor is to be able to edit/create animation for any object from the scene explorer. So if a node already has animations we should be able to edit/delete them and if there is no a simple right click should give us the opportunity to create one

The idea is to have it as a floating window (more like the node material editor) as there will be not enough room for it inside the inspector panel.

Part of this work is to also add a “Animations” UI when you select a node to be able to see the list of animations when selecting a node (as part of its properties)

[thomlucc]

Consolidating this issue in Inspector vNext Issue

[thomlucc]

Split back issue as we are getting closer to release.