Cleans Up WIP Event System + New Grid Check For It

Separates the 'count and assess everything' stuff to it's own datum, called the metric datum, which I plan to add on to in the future to make counting and metrics easier.
Makes decision process a bit more weight-based, will probably continue tweaking later.
Makes the admin debug UI have links to change settings easily.
Adds replacement for grid check event, which works similar to the old one, but is now based on a physical machine in the game world, that Engineering can hack to make the event end faster, if so desired.  Note that the machine is not mapped in, and won't be mapped in until the event system is ready for launch.
Adds grid_check variables to SMESes and APCs to make them stop doing work without draining the battery.
Grid checks in the new system are caused by a "power spike" which originates from the engine and will cause bad things, should no grid checker machine be connected to the power-net.  These power spikes occur when the GM decides that a grid check is a good event to have.
The grid checker can be built and deconstructed using the standard machine construction methods.

code/game/objects/items/weapons/circuitboards/machinery/power.dm

@@ -22,3 +22,10 @@
 	build_path = /obj/machinery/power/smes/batteryrack/makeshift
 	board_type = new /datum/frame/frame_types/machine
 	req_components = list(/obj/item/weapon/cell = 3)
+
+/obj/item/weapon/circuitboard/grid_checker
+	name = T_BOARD("power grid checker")
+	build_path = /obj/machinery/power/grid_checker
+	board_type = new /datum/frame/frame_types/machine
+	origin_tech = list(TECH_POWER = 4, TECH_ENGINEERING = 3)
+	req_components = list(/obj/item/weapon/stock_parts/capacitor = 3, /obj/item/stack/cable_coil = 10)