[DNM][DNM][WIP] Projectile backend code port and update

Ports#54924,  #65061, #59804 from /tg.
adds auxiliary code from /tg to make code work.

code/modules/projectiles/projectile/bullets/ferromagnetic.dm

@@ -28,7 +28,7 @@
 	damage = 10
 	armour_penetration = 20
 	stamina = 10
-	movement_type = FLYING | UNSTOPPABLE
+	movement_type = FLYING | PHASING
 	range = 6
 	fired_light_range = 1
 	fired_light_color = LIGHT_COLOR_RED
@@ -37,7 +37,7 @@
 	icon_state = "magjectile-large"
 	damage = 10
 	armour_penetration = 20
-	movement_type = FLYING | UNSTOPPABLE
+	movement_type = FLYING | PHASING
 	range = 20
 	pixels_per_second = TILES_TO_PIXELS(12.5)
 	fired_light_range = 4

code/modules/projectiles/projectile/bullets/sniper.dm

@@ -35,7 +35,8 @@
 	icon_state = "gauss"
 	name = "penetrator round"
 	damage = 60
-	movement_type = FLYING | UNSTOPPABLE
+	projectile_piercing = PASSMOB
+	projectile_phasing = (ALL & (~PASSMOB))
 	dismemberment = 0 //It goes through you cleanly.
 	knockdown = 0
 	breakthings = FALSE

code/modules/projectiles/projectile/bullets/special.dm

@@ -3,7 +3,8 @@
 /obj/item/projectile/bullet/honker
 	damage = 0
 	knockdown = 60
-	movement_type = FLYING | UNSTOPPABLE
+	movement_type = FLYING
+	projectile_piercing = ALL
 	nodamage = TRUE
 	candink = FALSE
 	hitsound = 'sound/items/bikehorn.ogg'