2D and 3D should use the same core systems

[Shadowblitz16]

Is your feature request related to a problem? Please describe.
2D and 3D should basically be the same thing except one has an extra dimension.

Describe the solution you'd like

• World origin starts at 0,0 for 2D and 0,0,0 for 3D.
• 0,0 is center of screen in 2D., just as 0,0,0 is center of world in 3D.
• 2D and 3D origin can be offset and monobehaviors don't break.
• 2D and 3D physics use same units of measurement and same algorithms
• UnitsPerPixel for both 2D and 3D.
• UnitsPerPixel should be set in game settings with override in the 2d and 3d transform monobehaviors.

Describe alternatives you've considered
Other game engines.

Additional context
NA

[michaelsakharov]

Thats pretty much already functional, you can already make a 2D game in the 3D space. Theres just no built in components for it just yet.
But yeah its gonna literally be identical to 3D almost everywhere, it just ignores the Z dimension but you could still use it for sorting i suppose.