Add Branding select to Resource form

For GLRI records only, we want to display a Select box containing the Institution's Branding options, if available.

Currently, we have this boolean field:

One complexity is how to know which Institution's Brandings to show in this select.

Since users can have >1 institution, we can't rely upon that.

If a Resource has already been created & saved, we can know the Resources' GLRI Institution and set based on that.

But on the NEW Resource form, I'm not sure what to do without resorting to JS.

This will also necessitate a has_one: :branding definition on the Resource