Cortical Borers (#21118)

Adds cortical borers, a midround antag originally from Bay. The code here is from yogstation, baystation and paradise station.

Borers are little brainslugs that when adjacent to a human can infest them. They can supply you with useful chemicals such as medicines and meth, and can revive you from the dead if they have maximum chemicals. They can also take over your body, putting them in control of you while you become a "captive mind". A captive mind can take back control by doing Resist. Health analyzers show borers in people, while medHUDs show borers in control. If you have Sugar in your body the borer can do nothing, it gets kicked out of control if it's controlling and becomes docile. Organ Manipulation surgery on head to remove the borer. If the brain of the body gets removed (decapitation, brain removal surgery, gibbing) the borer falls out of the host and loses control if they were controlling. Changelings can remove borers with Anatomic Panacea or Lesser Form (or Last Resort). Borers can reproduce and have an objective to escape on the shuttle with X hosts alive.

code/__DEFINES/role_preferences.dm

@@ -23,6 +23,7 @@
 #define ROLE_REVENANT			"revenant"
 #define ROLE_DEVIL				"devil"
 #define ROLE_SERVANT_OF_RATVAR	"servant of Ratvar"
+#define ROLE_BORER				"borer"
 
 //Missing assignment means it's not a gamemode specific role, IT'S NOT A BUG OR ERROR.
 //The gamemode specific ones are just so the gamemodes can query whether a player is old enough
@@ -45,6 +46,7 @@ var/global/list/special_roles = list(
 	ROLE_ABDUCTOR = /datum/game_mode/abduction,
 	ROLE_DEVIL = /datum/game_mode/devil,
 	ROLE_SERVANT_OF_RATVAR = /datum/game_mode/clockwork_cult,
+	ROLE_BORER,
 )
 
 //Job defines for what happens when you fail to qualify for any job during job selection