Allow resizing structures down to 2 cm instead of 16 cm.

[Jade-Harleyy]

I've ran into this problem a couple times, where I needed to have a resizable structure smaller than 16 cm, but I wasn't allowed to make it any smaller. This PR fixes that.

I chose 2 cm instead of 1 cm since the handles would overlap at 1 cm.

[mygamingaccount]

Fitting to grid size seems like an arbitrary choice, but then again so does 2. Why not 1?

[Jade-Harleyy]

Fitting to grid size seems like an arbitrary choice, but then again so does 2. Why not 1?

As I stated in the PR, I chose 2 as the minimum since, even when fully zoomed in, the resizing handles would overlap, making objects harder to work with.

[lewri]

While I'm not a person accustomed to the Barotrauma code I do question whether Barotrauma has a policy to deter magic numbers. You've replaced a standardised variable (Submarine.GridSize.X / Submarine.GridSize.Y) with a magic number (2) without context here given to it. It may be beneficial to give the number a single referenced point that then equals 2.
(of course if magic numbers aren't an issue to the devs I'll stay quiet and run away again 😅)

[mygamingaccount]

So basically int minResizableItemSize = 2;? Sounds fair.