Refactors virus spreading (#31066)

* Refactors virus spreading

* Cyberfixes

* Bump to infect

* proper shoe protection

* Split ContractDisease

* Makes virus severity matter

* oops

* Virus severity changes

* defines

* infective_floor --> infective

* Fixes vomit and pulling infection

code/datums/components/infective.dm

@@ -0,0 +1,13 @@
+/datum/component/infective
+	var/list/datum/disease/diseases //make sure these are the static, non-processing versions!
+
+/datum/component/infective/Initialize(list/datum/disease/_diseases)
+	RegisterSignal(COMSIG_MOVABLE_CROSSED, .proc/Infect)
+	diseases = _diseases
+
+/datum/component/infective/proc/Infect(atom/movable/AM)
+	var/mob/living/carbon/victim = AM
+	if(istype(victim))
+		for(var/datum/disease/D in diseases)
+			victim.ContactContractDisease(D, "feet")
+		return TRUE