feat: add widget.get_X and widget.get_Y

[alrun3]

Also adjusts unit.X and unit.Y to use GetWidget{X,Y} to align native calls. You may prefer the unit/item specific calls for jassdoc, in which case I'll happily update

[Orden4]

Replacing GetUnitX with GetWidgetX is no good. The widget variant has been benchmarked to just be straight slower, and 99% of the time you're going to be working with units, not widgets.

The approach I initially coded was actually to just duplicate the properties and hide the widget one via the new keyword, but at the time I'm fairly certain it caused compiler issues, but now it seems to be fine actually.

Lastly, I noticed that despite knowing about the GetWidgetX vs GetItemX performance difference, I'm not actually using it in item.cs currently for some reason...

So to summarize what this PR should do:

1. (Done) Add a get-only X/Y GetWidgetX/GetWidgetY to widget.cs
2. (Done) Remove the corresponding properties from destructable.cs
3. (To do) Change get X/Y of unit.cs to use GetUnitX/GetUnitY and add the new keyword
4. (To do) Change get+set X/Y of item.cs to use GetItemX/GetItemY and add the new keyword

[alrun3]

Cool, so exactly what I asked, but for performance and not UX 😁