[Feature] Add support for -1 extradmgskill to allow all skills to be scaled. (#3136)

* [Feature] Add support for -1 extradmgskill to allow all skills to be scaled.

- `$mob->GetSkillDmgAmt(skill_id)` now uses `int` instead of `uint16`.

- `statbonuses:GetSkillDamageAmount(skill_id)` now uses `-1` properly.
- `mob:GetSkillDmgAmt(skill_id)` now uses `int` instead of `uint16`.

- A `-1` value in `extradmgskill` denotes the ability to scale all skills at once.
- Consolidated `AddItemBonuses()`, `AdditiveWornBonuses()`, `CalcItemBonuses()`, and `CalcRecommendedLevelBonus()` to mob-based methods to avoid code duplication.
- Bots, NPCs, and Mercs can now use additive worn effects if the rule is enabled, as well as all other proper stat bonuses that only clients had before.
- No SQL update required to change `extradmgskill` and `extradmgamt` to `int` as they already are this type in the database, just had to adjust `item_data.h` and `shareddb.cpp`.

* Update mob.cpp

* Cleanup.

* Cleanup.

* Move #include <vector> to header.

* Add method for GetExtraDamageSkills

* fix additembonuses

* Update bonuses.cpp

* Update mob.cpp

* Out of bounds.

* Update bonuses.cpp

---------

Co-authored-by: Aeadoin <109764533+Aeadoin@users.noreply.github.com>

zone/lua_stat_bonuses.cpp

@@ -1,5 +1,7 @@
 #ifdef LUA_EQEMU
 
+#include "../common/data_verification.h"
+
 #include "lua.hpp"
 #include <luabind/luabind.hpp>
 
@@ -1097,7 +1099,11 @@ int32 Lua_StatBonuses::GetSkillReuseTime(int idx) const {
 
 int32 Lua_StatBonuses::GetSkillDamageAmount(int idx) const {
 	Lua_Safe_Call_Int();
-	return self->SkillDamageAmount[idx];
+	if (!EQ::ValueWithin(idx, ALL_SKILLS, EQ::skills::HIGHEST_SKILL)) {
+		return 0;
+	}
+
+	return idx == ALL_SKILLS ? self->SkillDamageAmount[EQ::skills::HIGHEST_SKILL + 1] : self->SkillDamageAmount[idx];
 }
 
 int Lua_StatBonuses::GetHPPercCap(int idx) const {