Hold SHIFT on XY resizing handles to maintain aspect ratio

[JansenSmith]

Only need to modify https://github.com/CommonWealthRobotics/CaDoodle-Application/blob/main/src/main/java/com/commonwealthrobotics/controls/ResizeSessionManager.java

Looks like the handle logic is already generic, located here:
https://github.com/CommonWealthRobotics/CaDoodle-Application/blob/main/src/main/java/com/commonwealthrobotics/controls/ResizingHandle.java

[JansenSmith]

Can calculate scale from:

A - Diagonal distance change (most geometrically pure)
B - Average of X-scale and Y-scale changes
C - Maximum of X-scale or Y-scale (maintains one dimension precisely)

I'm gonna go with maximum, for now, to see if it has a weird UI feel.

[madhephaestus]

In the meantime, this uniform resize works with the Z handle. Hold shift while dragging the z height will perform a uniform resize and snap the height to the given value, while scaling the x and y accordingly.

[rondlh]

Right, uniform scaling with the Z-handle works very well.

Reference #96