Replaces world.icon_size (and some magic numbers) with defines (#86819)

## About The Pull Request

All usages of world.icon_size in code have been replaced with new
`ICONSIZE_X`, `ICONSIZE_Y` and `ICONSIZE_ALL` defines depending on
context

Replaces some "32" magic numbers with the defines

A few bits of code have been modified to split up x/y math as well

## Why It's Good For The Game

Magic number bad, code more readable, code more flexible and I'm told
there's an access cost to doing world.icon_size so minor performance
gains

## Changelog

🆑 tonty
code: made some code relating to the world's icon size more readable
/🆑

---------

Co-authored-by: Ghom <42542238+Ghommie@users.noreply.github.com>

code/modules/tooltip/tooltip.dm

@@ -37,7 +37,7 @@ Notes:
 
 
 /datum/tooltip/proc/show(atom/movable/thing, params = null, title = null, content = null, theme = "default", special = "none")
-	if (!thing || !params || (!title && !content) || !owner || !isnum(world.icon_size))
+	if (!thing || !params || (!title && !content) || !owner || !isnum(ICON_SIZE_ALL))
 		return FALSE
 
 	if (!isnull(last_target))
@@ -50,7 +50,7 @@ Notes:
 	if (!init)
 		//Initialize some vars
 		init = 1
-		owner << output(list2params(list(world.icon_size, control)), "[control]:tooltip.init")
+		owner << output(list2params(list(ICON_SIZE_ALL, control)), "[control]:tooltip.init")
 
 	showing = 1