Fullscreen overlay rework, full-black unconsciousness overlay, overlay fadeout animations + more. (#10053)

Ported the clickcatcher from tg/bay. You can now click black spots to turn. Isn't that handy, especially with vision cones.

    Reworked fullscreen overlays into an easier and better system, courtesy of PsiOmegaDelta.

    Similiarly, added fadeout animations to all pain overlays, plus unconsciousness.

    Fixed the vampire frenzy overlay never showing.

    Unconsciousness is now FULL darkness.

    Flashing mobs is now an inbuilt proc.

code/_helpers/turfs.dm

@@ -43,6 +43,19 @@
 	if(turfs.len)
 		return pick(turfs)
 
+/proc/screen_loc2turf(text, turf/origin)
+	if(!origin)
+		return null
+	var/tZ = splittext(text, ",")
+	var/tX = splittext(tZ[1], "-")
+	var/tY = text2num(tX[2])
+	tX = splittext(tZ[2], "-")
+	tX = text2num(tX[2])
+	tZ = origin.z
+	tX = max(1, min(origin.x + 7 - tX, world.maxx))
+	tY = max(1, min(origin.y + 7 - tY, world.maxy))
+	return locate(tX, tY, tZ)
+
 // This proc will check if a neighboring tile in the stated direction "dir" is dense or not
 // Will return 1 if it is dense and zero if not
 /proc/check_neighbor_density(turf/T, var/dir)