[wpilib] Field2d enhancements

[PeterJohnson]

• Add raw support for pose lists > 255/3 in length
• Improve drag selection, especially with closely overlapping objects
• Drag selection of corner also highlights center of object with smaller circle
• Multiple styles (box, line, closed line, track)
• Configurable line and arrow settings (color, weight)
• Add tooltip for object name, index, x, y, rotation
• Context menu for pose edit/add/remove
• View/edit in feet or inches as well as meters
• Configurable object selectability

Implementation: use vector of Pose2d internally, use units

Fixes #3197.