Goal tracker window support

[davidmc24]

This first pass is relatively simple. It only supports a single display with "collected" vs "uncollected". It doesn't have any support for tracking rares, max, max rares, etc.

It should remember whether the window is open, as well as if it has been resized/moved.

[GurliGebis]

Looks good - we can always expand on the functionality later on 🙂