Makes ruin budget proportional to amount of space ruin z-levels (#74841)

## About The Pull Request
Adds global define for DEFAULT_SPACE_RUIN_LEVELS and
DEFAULT_SPACE_EMPTY_LEVELS

### Proportional budget
Adds proportional budget to setup_ruins
The budget is multiplied by the current amount of ruin levels over the
default amount
Smaller amounts will have less ruins, while bigger maps will have more
ruins
Should maintain the same amount of ruins per z-level


### Z-levels spawning fix
Z-levels didn't seem to spawn their intended amount of ruins
This was because the for loop added the count variable before doing the
spawning. So for example if there was only 1 level, it would count to 1
and end the loop without spawning the level.
Also removed a loop that seemed to just make the process more complex
for no reason. It even had a note to remove it. However, if it has a use
then you should tell me.

## Why It's Good For The Game

Maps with a smaller amount of ruin levels won't be completely filled
The amount of ruins will be consistent per z-level
The creator of North Star won't allow space exploration unless there's a
way to proportionally reduce the space budget see #74719
## Changelog
🆑
fix: Maps now spawn the correct amount of space levels. The bug caused
them to spawn 1 less in each category
code: The space ruins budget is now proportional to the amount of ruin
levels. This has no effect on the current default maps, but added maps
with less than the default amount of ruin levels will see less ruins.
/🆑

code/controllers/subsystem/mapping.dm

@@ -130,12 +130,12 @@ SUBSYSTEM_DEF(mapping)
 #ifndef LOWMEMORYMODE
 	// Create space ruin levels
 	while (space_levels_so_far < config.space_ruin_levels)
+		add_new_zlevel("Ruin Area [space_levels_so_far+1]", ZTRAITS_SPACE)
 		++space_levels_so_far
-		add_new_zlevel("Empty Area [space_levels_so_far]", ZTRAITS_SPACE)
-	// and one level with no ruins
-	for (var/i in 1 to config.space_empty_levels)
+	// Create empty space levels
+	while (space_levels_so_far < config.space_empty_levels + config.space_ruin_levels)
+		empty_space = add_new_zlevel("Empty Area [space_levels_so_far+1]", list(ZTRAIT_LINKAGE = CROSSLINKED))
 		++space_levels_so_far
-		empty_space = add_new_zlevel("Empty Area [space_levels_so_far]", list(ZTRAIT_LINKAGE = CROSSLINKED))
 
 	// Pick a random away mission.
 	if(CONFIG_GET(flag/roundstart_away))
@@ -251,7 +251,9 @@ SUBSYSTEM_DEF(mapping)
 	// Generate deep space ruins
 	var/list/space_ruins = levels_by_trait(ZTRAIT_SPACE_RUINS)
 	if (space_ruins.len)
-		seedRuins(space_ruins, CONFIG_GET(number/space_budget), list(/area/space), themed_ruins[ZTRAIT_SPACE_RUINS])
+		// Create a proportional budget by multiplying the amount of space ruin levels in the current map over the default amount
+		var/proportional_budget = round(CONFIG_GET(number/space_budget) * (space_ruins.len / DEFAULT_SPACE_RUIN_LEVELS))
+		seedRuins(space_ruins, proportional_budget, list(/area/space), themed_ruins[ZTRAIT_SPACE_RUINS])
 
 /// Sets up rivers, and things that behave like rivers. So lava/plasma rivers, and chasms
 /// It is important that this happens AFTER generating mineral walls and such, since we rely on them for river logic
@@ -422,10 +424,6 @@ Used by the AI doomsday and the self-destruct nuke.
 		qdel(query_round_map_name)
 
 #ifndef LOWMEMORYMODE
-	// TODO: remove this when the DB is prepared for the z-levels getting reordered
-	while (world.maxz < (5 - 1) && space_levels_so_far < config.space_ruin_levels)
-		++space_levels_so_far
-		add_new_zlevel("Empty Area [space_levels_so_far]", ZTRAITS_SPACE)
 
 	if(config.minetype == "lavaland")
 		LoadGroup(FailedZs, "Lavaland", "map_files/Mining", "Lavaland.dmm", default_traits = ZTRAITS_LAVALAND)