[MIRROR] slight teg (circulator) icon update (#683)

* slight teg (circulator) icon update (#81117)

## About The Pull Request
This PR changes the circulator's sprite to have four informational
overlays-- one will display the panel status (opened or closed), one
will show if the circulators are anchored (or not), one that will show
if it is on the hot or cold mode, and what direction the gas will flow
from "inside" the circulator.
## Why It's Good For The Game
Using sprites to promote clarity is nice...


![image](https://github.com/tgstation/tgstation/assets/55967837/fa76a7d5-57fc-4408-a0ab-798d0aa4cdef)
## Changelog
:cl:
code: added the code that allows the image overlays to work for the
circulator (teg)
image: changed circulator's (teg) fast/slow turbine sprite
image: added an anchor, panel, and flow overlay for the circulator (teg)
/:cl:

* slight teg (circulator) icon update

---------

Co-authored-by: jjpark-kb <[email protected]>

code/modules/atmospherics/machinery/components/binary_devices/circulator.dm

@@ -4,7 +4,7 @@
 /obj/machinery/atmospherics/components/binary/circulator
 	name = "circulator/heat exchanger"
 	desc = "A gas circulator pump and heat exchanger."
-	icon_state = "circ-off-0"
+	icon_state = "circ_base"
 	pipe_flags = PIPING_ONE_PER_TURF | PIPING_DEFAULT_LAYER_ONLY
 	vent_movement = VENTCRAWL_CAN_SEE
 	density = TRUE
@@ -59,19 +59,25 @@
 /obj/machinery/atmospherics/components/binary/circulator/process_atmos()
 	update_appearance()
 
-/obj/machinery/atmospherics/components/binary/circulator/update_icon_state()
+/obj/machinery/atmospherics/components/binary/circulator/update_overlays()
+	. = ..()
+	cut_overlays()
+	if(anchored)
+		add_overlay("circ_anchor")
+	add_overlay("panel_[panel_open]")
+
 	if(!is_operational)
-		icon_state = "circ-p-[flipped]"
-		return ..()
-	if(last_pressure_delta > 0)
-		if(last_pressure_delta > ONE_ATMOSPHERE)
-			icon_state = "circ-run-[flipped]"
-		else
-			icon_state = "circ-slow-[flipped]"
-		return ..()
+		add_overlay("fan_[mode]")
+		add_overlay("flow")
+		add_overlay("display")
+		return
 
-	icon_state = "circ-off-[flipped]"
-	return ..()
+	add_overlay("flow_on")
+	add_overlay("display_[mode]")
+	if(last_pressure_delta > 0)
+		add_overlay("fan_[mode]_[last_pressure_delta > ONE_ATMOSPHERE]")
+	else
+		add_overlay("fan_[mode]")
 
 /obj/machinery/atmospherics/components/binary/circulator/wrench_act(mob/living/user, obj/item/I)
 	if(!panel_open)