Adds NO_ALERT flag to areas, refactors area alerts slightly (#752)

Co-authored-by: msgerbs <msgerbs@users.noreply.github.com>
Co-authored-by: Azarak <azarak10@gmail.com>

code/modules/awaymissions/mission_code/moonoutpost19.dm

@@ -23,7 +23,6 @@
 	power_environ = FALSE
 	power_equip = FALSE
 	power_light = FALSE
-	poweralm = FALSE
 	ambientsounds = list('sound/ambience/ambimine.ogg')
 	icon_state = "awaycontent5"
 
@@ -33,7 +32,6 @@
 	power_environ = FALSE
 	power_equip = FALSE
 	power_light = FALSE
-	poweralm = FALSE
 	icon_state = "awaycontent6"
 
 //Papers

code/modules/awaymissions/mission_code/undergroundoutpost45.dm

@@ -36,4 +36,3 @@
 	power_environ = FALSE
 	power_equip = FALSE
 	power_light = FALSE
-	poweralm = FALSE

code/modules/power/apc.dm

@@ -1245,24 +1245,24 @@
 			equipment = autoset(equipment, 0)
 			lighting = autoset(lighting, 0)
 			environ = autoset(environ, 0)
-			area.poweralert(0, src)
+			area.poweralert(TRUE, src)
 		else if(cell.percent() < 15 && longtermpower < 0)	// <15%, turn off lighting & equipment
 			equipment = autoset(equipment, 2)
 			lighting = autoset(lighting, 2)
 			environ = autoset(environ, 1)
-			area.poweralert(0, src)
+			area.poweralert(TRUE, src)
 		else if(cell.percent() < 30 && longtermpower < 0)			// <30%, turn off equipment
 			equipment = autoset(equipment, 2)
 			lighting = autoset(lighting, 1)
 			environ = autoset(environ, 1)
-			area.poweralert(0, src)
+			area.poweralert(TRUE, src)
 		else									// otherwise all can be on
 			equipment = autoset(equipment, 1)
 			lighting = autoset(lighting, 1)
 			environ = autoset(environ, 1)
-			area.poweralert(1, src)
+			area.poweralert(FALSE, src)
 			if(cell.percent() > 75)
-				area.poweralert(1, src)
+				area.poweralert(FALSE, src)
 
 		// now trickle-charge the cell
 		if(chargemode && charging == APC_CHARGING && operating)
@@ -1304,7 +1304,7 @@
 		equipment = autoset(equipment, 0)
 		lighting = autoset(lighting, 0)
 		environ = autoset(environ, 0)
-		area.poweralert(0, src)
+		area.poweralert(TRUE, src)
 
 	// update icon & area power if anything changed
 

code/modules/power/singularity/investigate.dm

@@ -1,4 +0,0 @@
-/area/engine/engineering/poweralert(state, source)
-	if (state != poweralm)
-		investigate_log("has a power alarm!", INVESTIGATE_SINGULO)
-	..()