Update default properties to include 3D UI objects

[dphfox]

There are many cases where Fusion may be used for 3D UI and visualisations. for example placing SurfaceGuis on floating panels for VR games, draggers and adornments, viewport frame contents, and many more.

To aid with these uses, I propose introducing the following changes to the defaultProps list used by New:

• HandleAdornments should have a ZIndex of 0 - Roblox defaults these to -1, which causes colour artifacts when AlwaysOnTop, and anyway 0 makes more sense as a base value
• Parts should be Anchored - the logic here is that parts are almost always desired to be static objects, with physics being an exceptional case only opted into sometimes, especially in the context of UI.
• Parts should not have studs or inlets by default - this is legacy and not supported in modern Roblox
• Parts should have a unit size (1, 1, 1), rather than the legacy 'smooth block' size
• SpawnLocation should have a ForceField duration of 0 - force fields are generally not used in modern games

This is almost certainly a breaking change for any UI that deals with these primitives.