[MDB IGNORE] Grayscale sofas (#71539)

## About The Pull Request
Ports some sofa sprites from over at
https://github.com/BeeStation/BeeStation-Hornet/pull/7547 and makes them
grayscale. Also random tool colours now use defines.


![image](https://user-images.githubusercontent.com/66640614/204077835-94b713a9-a7e5-42fc-8c65-5724ca11cc4a.png)


![image](https://user-images.githubusercontent.com/66640614/204077844-87b33cda-d829-4ebb-a81f-a5e05453999d.png)

## Why It's Good For The Game
Gives us the opportunity to make different coloured couches more easily.
## Changelog

🆑 Tattle, PestoVerde322
imageadd: couches are now grayscale
code: random tool colours now use defines
/🆑

Co-authored-by: tattle <article.disaster@gmail.com>

code/game/objects/structures/beds_chairs/sofa.dm

@@ -1,6 +1,20 @@
+/// Create colored subtypes for sofas
+#define COLORED_SOFA(path, color_name, sofa_color) \
+path/middle/color_name {\
+	color = sofa_color; \
+} \
+path/right/color_name {\
+	color = sofa_color; \
+} \
+path/left/color_name {\
+	color = sofa_color; \
+} \
+path/corner/color_name {\
+	color = sofa_color; \
+}
+
 /obj/structure/chair/sofa
 	name = "old ratty sofa"
-	icon_state = "sofamiddle"
 	icon = 'icons/obj/sofa.dmi'
 	buildstackamount = 1
 	item_chair = null
@@ -46,6 +60,9 @@
 /obj/structure/chair/sofa/corner/handle_layer() //only the armrest/back of this chair should cover the mob.
 	return
 
+/obj/structure/chair/sofa/middle
+	icon_state = "sofamiddle"
+
 /obj/structure/chair/sofa/left
 	icon_state = "sofaend_left"
 
@@ -55,6 +72,9 @@
 /obj/structure/chair/sofa/corner
 	icon_state = "sofacorner"
 
+COLORED_SOFA(/obj/structure/chair/sofa, brown, SOFA_BROWN)
+COLORED_SOFA(/obj/structure/chair/sofa, maroon, SOFA_MAROON)
+
 // Original icon ported from Eris(?) and updated to work here.
 /obj/structure/chair/sofa/corp
 	name = "sofa"
@@ -111,3 +131,5 @@
 
 /obj/structure/chair/sofa/bamboo/right
 	icon_state = "bamboo_sofaend_right"
+
+#undef COLORED_SOFA