* This is PHASE 1 of a multi-phase conversion. In this first phase we implement the subsystem, but leave it processing the existing global list variables. In the next phase we will switch to use datum variables in the subsystem. The main reason for splitting into two phases is ease of code review; change the meaningful code without the hundreds of machines -> SSmachines.machinery substitutions.
* We did declare macros for adding/removing things to the processing lists, and convert everywhere to use the macros.
* Added var/is_processing to /datum to keep track of whether an instance is already in a processing list (prevents it being in the list twice!) and also debugging, making sure its not in two lists etc.
* NOTE: The global machines list is **no longer sorted** for performance reasons. As far as I know, the only module that actually ever cared was cameras. Our camera system already handles its own sorting in the cameranets anyway, so it should no longer be needed.
* Adds defines for world.tick_usage
* This provides no useful benefit whatsoever, but /tg and Baystation12 have done it, so it will make porting future code easier if we do too. No real harm done either.
Mostly ports /tg/'s method of seeding submaps into specific z-levels.
Due to the low number of submaps present, all of the PoIs are guaranteed to spawn. As more are added, this should fix itself.
New lighting system is needed to handle updating literally 14k+ tiles whenever the sun moves. The straight port seems to have had no adverse effects from what I could see. Don't know if it's more performant but it doesn't seem to be less.
I didn't expect the latter would be needed for the former.
* Based on https://github.com/tgstation/tgstation/pull/25386
* Create macro for defining new subsystem types.
* Create PreInit proc to handle setup that needs to be done before the map loads
* Rename garbage_controller subsystem to garbage so it matches its global SSgarbage variable name.
