General maintenance for plumbing disposer (#94944)

## About The Pull Request
- Plumbing disposer disposal rate can now be changed with hand nad has
TGUI interface. It accepts a value between 5->15 meaning it can dispose
anywhere from 10u to 50u reagents per tick. Added examines & screen tips
for the same
- Fixes plumbing disposer icon state not correctly switching between
working and off under certain circumstances

## Changelog
🆑
qol: plumbing disposer now has TGUI interface for operations
fix: plumbing disposer icon state correctly switches between on & off
under circumstances
/🆑

code/datums/components/plumbing/simple_components.dm

@@ -20,6 +20,19 @@
 		edge_overlay.pixel_z = -parent_movable.pixel_y - parent_movable.pixel_z
 		overlays += edge_overlay
 
+///For disposing reagents
+/datum/component/plumbing/simple_demand/disposer
+
+/datum/component/plumbing/simple_demand/disposer/Initialize(ducting_layer, distinct_reagent_cap)
+	if(!istype(parent, /obj/machinery/plumbing/disposer))
+		return COMPONENT_INCOMPATIBLE
+	return ..()
+
+/datum/component/plumbing/simple_demand/disposer/send_request(dir)
+	var/obj/machinery/plumbing/disposer/target = parent
+	if(target.on)
+		process_request(target.disposal_rate * SSFLUIDS_DT, dir = dir)
+
 ///has one pipe output that only supplies. example is liquid pump and manual input pipe
 /datum/component/plumbing/simple_supply
 	supply_connects = SOUTH