Gizmo 3d grids

[lynn-lumen]

Objective

• Adds 3d grids, suggestion of Tracking issue: Amazing Gizmos #9400

Solution

• Added 3d grids (grids spanning all three dimensions, not flat grids) to bevy_gizmos

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Changelog

• gizmos.grid(...) and gizmos.grid_2d(...) now return a GridBuilder2d.
• Added gizmos.grid_3d(...) which returns a GridBuilder3d.
  • The difference between them is basically only that GridBuilder3d exposes some methods for configuring the z axis while the 2d version doesn't.
• Allowed for drawing the outer edges along a specific axis by calling .outer_edges_x(), etc. on the builder.

Additional information

Please note that I have not added the 3d grid to any example as not to clutter them.
Here is an image of what the 3d grid looks like:

[lynn-lumen]

Apparently there is something wrong with bevy_reflect. Can someone help here?
😅

[alice-i-cecile]

#12433 should fix the CI failure :)

[pablo-lua]

Looks good, I just have a few comments