gp32.xml: Metadata cleanups

[ArcadeShadow]

Replaced countries' abbreviations by their full name
Moved test comments to notes tag

[rb6502]

I don't think any of the "boot OK" comments or notes are necessary. If something is supported="yes" or "partial" that means that it boots, and for "partial" you can list just the problems (graphics glitches or save problems or whatever) as a note.

[angelosa]

Yeah, boot OK can be safely removed from everything, it's a worthless anchor/adds nothing of value particularly since we consolidated that supported=<undefined> is a better alias for stuff that isn't tested at least once.

[ArcadeShadow]

done it.