[Spells] Rework of Virus Effect code (#1593)

* start of rework

* functional

* virus updates

* Update npc.cpp

* updates

* updates

* update v2

* pre remove old code

* removed old code1

* remove debugs

* description

* Update spell_effects.cpp

* changed function name

* remove unused var

* merge error fix

* fix formating issue

* Update spdat.cpp

* Update spell_effects.cpp

* Convert virus entity range code to use vectors and GetCloseMobList

* Formatting [skip ci]

Co-authored-by: Akkadius <akkadius1@gmail.com>

zone/common.h

@@ -330,6 +330,7 @@ struct Buffs_Struct {
 	uint32	instrument_mod;
 	int16   focusproclimit_time;	//timer to limit number of procs from focus effects 
 	int16   focusproclimit_procamt; //amount of procs that can be cast before timer limiter is set
+	int32	virus_spread_time; //time till next attempted viral spread
 	bool	persistant_buff;
 	bool	client; //True if the caster is a client
 	bool	UpdateClient;