[FIX] Better slices (#27807)

* Slices have a base class /food/slice

* Refactor

* Small fix

* Adds default reagent for empy slices

* Looks good

* adds_list_reagents

* "Reverted snake_case_remap files to state from original commit

* I don't know how to resolve merge conflicts :)

---------

Signed-off-by: Drsmail <60036448+Drsmail@users.noreply.github.com>

code/modules/hydroponics/grown/melon.dm

@@ -26,7 +26,7 @@
 	name = "watermelon"
 	desc = "It's full of watery goodness."
 	icon_state = "watermelon" // Sprite created by https://github.com/binarysudoku for Goonstation, They have relicensed it for our use.
-	slice_path = /obj/item/food/watermelonslice
+	slice_path = /obj/item/food/sliced/watermelon
 	slices_num = 5
 	dried_type = null
 	w_class = WEIGHT_CLASS_NORMAL

code/modules/hydroponics/grown/onion.dm

@@ -23,7 +23,7 @@
 	icon_state = "onion"
 	filling_color = "#C0C9A0"
 	bitesize_mod = 2
-	slice_path = /obj/item/food/onion_slice
+	slice_path = /obj/item/food/sliced/onion_slice
 	tastes = list("onion" = 1, "pungentness" = 1)
 	slices_num = 2
 	wine_power = 0.3
@@ -46,12 +46,12 @@
 	desc = "Purple despite the name."
 	icon_state = "onion_red"
 	filling_color = "#C29ACF"
-	slice_path = /obj/item/food/onion_slice/red
+	slice_path = /obj/item/food/sliced/onion_slice/red
 	tastes = list("red onion" = 1, "pungentness" = 3)
 	wine_power = 0.6
 	wine_flavor = "powerful pungentness"
 
-/obj/item/food/onion_slice
+/obj/item/food/sliced/onion_slice
 	name = "onion slices"
 	desc = "Rings, not for wearing."
 	icon_state = "onionslice"
@@ -61,7 +61,7 @@
 	gender = PLURAL
 	cooked_type = /obj/item/food/onionrings
 
-/obj/item/food/onion_slice/red
+/obj/item/food/sliced/onion_slice/red
 	name = "red onion slices"
 	desc = "They shine like exceptionally low quality amethyst."
 	icon_state = "onionslice_red"

code/modules/hydroponics/grown/pineapple.dm

@@ -25,7 +25,7 @@
 	attack_verb = list("stung", "pined")
 	throw_speed = 1
 	throw_range = 5
-	slice_path = /obj/item/food/pineappleslice
+	slice_path = /obj/item/food/sliced/pineapple
 	slices_num = 3
 	filling_color = "#F6CB0B"
 	w_class = WEIGHT_CLASS_NORMAL

code/modules/hydroponics/grown/tomato.dm

@@ -19,7 +19,7 @@
 	name = "tomato"
 	desc = "I say to-mah-to, you say tom-mae-to."
 	icon_state = "tomato"
-	slice_path = /obj/item/food/tomatoslice
+	slice_path = /obj/item/food/sliced/tomato
 	slices_num = 4
 	splat_type = /obj/effect/decal/cleanable/tomato_smudge
 	filling_color = "#FF6347"