"Add instance"/"Set number of instances" should add instances in a grid

Is your feature request related to a problem? Please describe. The current add instance functionality is essentially useless without arrange, and using large quantities can be annoying, especially now that multiple beds are a thing. If you add enough instances so that the object goes off the build plate (especially if not positioned near 0,0), you can't really just use arrange very quickly - and even if you can use arrange, more often than not you don't get a neat rectangular arrangement of objects that I generally try to have. Or, instead of a nice 4x4 grid of objects, they get thrown about.

Describe the solution you'd like Currently what happens if you click "add instance" 4 times or set number of instances to 5. You can't really do much with that as-is.

My proposal: Using the Spacing setting from the arrange, add instances in a grid pattern.

Objects should be added in a way so that the bounding box of the entire selection is as square as possible (or for example for MK3/4/C1, as print-bed-shaped as possible).

Here's the order in which objects would appear if clicking "Add instance" one by one. Of course, I would not expect to be able to select something else and then go back to adding objects in that exact same grid - but it would be neat to be able to.

(may not be mathematically accurate as displayed)

This should be a relatively simple and reliable way to do a grid arrange without adding it as an option in arrange itself, and it makes "Add instances" useful on its own.

Describe alternatives you've considered Quite a few times I've used arrange and then manually deleted the extra objects that were added, but if you're trying to fill a build plate it generally doesn't work that well. Fill bed with instances is not great if you've got other stuff on the bed as well.