Fixes #8270

Fixes part where alcohol potency was doubled and halves drinking glass volume so it won't hold a half of a bottle.
Also set bottle/shaker volumes to new 30u base most reagent containers like beakers/bottles use nowdays as requested.

code/modules/reagents/reagent_containers/food/drinks.dm

@@ -271,7 +271,7 @@
 	desc = "A metal shaker to mix drinks in."
 	icon_state = "shaker"
 	amount_per_transfer_from_this = 10
-	volume = 100
+	volume = 120
 	center_of_mass = list("x"=17, "y"=10)
 
 /obj/item/weapon/reagent_containers/food/drinks/flask

code/modules/reagents/reagent_containers/food/drinks/bottle.dm

@@ -6,7 +6,7 @@
 
 /obj/item/weapon/reagent_containers/food/drinks/bottle
 	amount_per_transfer_from_this = 10
-	volume = 100
+	volume = 120
 	item_state = "broken_beer" //Generic held-item sprite until unique ones are made.
 	var/const/duration = 13 //Directly relates to the 'weaken' duration. Lowered by armor (i.e. helmets)
 	var/isGlass = 1 //Whether the 'bottle' is made of glass or not so that milk cartons dont shatter when someone gets hit by it

code/modules/reagents/reagent_containers/food/drinks/drinkingglass.dm

@@ -4,8 +4,8 @@
 	name = "glass"
 	desc = "Your standard drinking glass."
 	icon_state = "glass_empty"
-	amount_per_transfer_from_this = 10
-	volume = 50
+	amount_per_transfer_from_this = 5
+	volume = 30
 	center_of_mass = list("x"=16, "y"=10)
 
 	on_reagent_change()
@@ -16,24 +16,24 @@
 		/*else if(reagents.reagent_list.len == 1)
 			for(var/datum/reagent/R in reagents.reagent_list)
 				switch(R.id)*/
-		if (reagents.reagent_list.len > 0)
+		if (reagents.reagent_list.len > 0)
 			var/datum/reagent/R = reagents.get_master_reagent()
-			
+
 			if(R.glass_icon_state)
 				icon_state = R.glass_icon_state
 			else
 				icon_state = "glass_brown"
-			
+
 			if(R.glass_name)
 				name = R.glass_name
 			else
 				name = "Glass of.. what?"
-			
+
 			if(R.glass_desc)
 				desc = R.glass_desc
 			else
 				desc = "You can't really tell what this is."
-			
+
 			if(R.glass_center_of_mass)
 				center_of_mass = R.glass_center_of_mass
 			else