Add rectangular cuboid shape

[e00E]

Based on #377 updated to current master.

I have renamed Prism to Cuboid because this is a more common name and easier to search for.

[e00E]

I see that CI is currently failing on master unrelated to this PR.

[cart]

yeah. our math library glam pushed out a minor version change that deprecated accessor methods like .x(). We've fixed that on master, so a rebase + force push should resolve the issue.

[cart]

I think this should either be called Cuboid, RectangularPrism, or just Box (Box has my preference, but it also collides with the rust Box type, so we probably shouldn't use that). RectangularCuboid is redundant.

Lets also take this chance to correct the "cube" shape size and divide the min/max extents by 2.0. Lets just use the Cuboid constructor for simplicity.

[e00E]

Renamed to Cuboid. Wikipedia claims a cuboid is more general than what we have which is a rectangular cuboid. Imo either name is fine.

Also changed the constructor's length, width, height to be x_length, y_length, z_length to make it clear which axis this refers to.

Lets also take this chance to correct the "cube" shape size and divide the min/max extents by 2.0. Lets just use the Cuboid constructor for simplicity.

Not sure exactly what you mean. I have now removed the old Cube because Cuboid can be used just as easily. In Cuboid the extents are already correct, right?

[cart]

Ah yeah wikipedia does say that "sheared" rectangular prisms are also cuboids. I think its better to roll with the Box name at this point. Its the most intuitive and namespacing can always protect against collisions. I re-added Cube because I think its a common enough shape to merit a "shortcut" that encodes intent. I also moved the shapes module to their own file for better organization.