Add precision mode for the tool

[Zac8668]

The tool currently just sucks and shoots atoms in a "messy" way.
But to support some better terrain control we need to add a precision mode. With it you would be able to place the atoms in a square and/or circle shape, and also remove atoms in the same shape, allowing the placement of solids that do not move.

[erlend-sh]

So we seem to be talking about at least two different modes of placement here?

• Atom-placement by projectile: Atoms come flying out of our atom-shooting gun.
• Atom-placement by spawning: Atoms appear in a selected location out of thin air, as if teleported from your canister.

Each mode has different possible shapes:

Projectile

• Wide spray
• Single stream
• etc.

Spawning

• Rectangle
• Circle
• etc.

[Zac8668]

• Atom-placement by spawning: Atoms appear in a selected location out of thin air, as if teleported from your canister.

We can make particles that follow where the atom would be placed, and them place themselves there, kinda like the tool has a "smart placing" tech.