Remove a whole bunch of in world loops and rework machinery global lists (#3053)

Removes a whole bunch of in world loops.
Reworks SSmachinery to hold two lists: all_machines and processing_machines. all_machines contains all machines 5ever. All of them. Literally. Forever. And ever. processing_machines only contains machines that process with the SSmachinery controller.

I checked most types at runtime on the live server to see whether they're in processing_machines or in all_machines, and did debug to ensure that most machinery ends up and stays in all_machines.

Includes a basic UT to make sure all mapped in machinery types remain within the all_machines list post-init.

code/controllers/subsystems/processing/pipenet.dm

@@ -9,7 +9,7 @@ var/datum/controller/subsystem/processing/pipenet/SSpipenet
 	NEW_SS_GLOBAL(SSpipenet)
 
 /datum/controller/subsystem/processing/pipenet/Initialize(timeofday)
-	for (var/obj/machinery/atmospherics/machine in machines)
+	for (var/obj/machinery/atmospherics/machine in SSmachinery.processing_machines)
 		machine.build_network()
 
 		CHECK_TICK

code/controllers/subsystems/processing/shuttle.dm

@@ -20,7 +20,7 @@ var/datum/controller/subsystem/processing/shuttle/shuttle_controller
 		shuttle.init_docking_controllers()
 		shuttle.dock() //makes all shuttles docked to something at round start go into the docked state
 
-	for(var/obj/machinery/embedded_controller/C in machines)
+	for(var/obj/machinery/embedded_controller/C in SSmachinery.processing_machines)
 		if(istype(C.program, /datum/computer/file/embedded_program/docking))
 			C.program.tag = null //clear the tags, 'cause we don't need 'em anymore