Graph Editor / Viewer : Add Token Support to the UI

[kwokcb]

Issue

If you have a document using tokens, these do not show up anywhere in the UI.

Proposal

Allow them to at least show up in the property panel for each as editable / non-connectable values. Suggest that they do not show up as pins on nodes in the editor as they can't be connected.

The issue is broken into 2 sub-issues:

• [x] First for just getting tokens to show up. Completed.
• [ ] 2nd to add in editing and render update support.

[xipaja]

Hello, I'm interested in taking this on for Dev Days!

[jstone-lucasfilm]

Welcome, @xipaja!

[kwokcb]

I've split this issue into 2 parts so we can close the first part and leave the second (editing) open. @xipaja what your working is only the first part.