[Feature] Instance Version Specific Experience Modifiers (#2376)

* [Feature] Add Instance Version Support to Experience Modifiers.

Allows Operators to set experience modifiers to be instance version specific so that you can have different versions of the same zone have different modifiers. If there is not one found, it defaults to zone_id 0 for global and instance_veresion -1 for global.

* Update zonedb.cpp

* Typo.

utils/sql/git/required/2022_08_14_exp_modifier_instance_versions.sql

@@ -0,0 +1,4 @@
+ALTER TABLE character_exp_modifiers 
+ADD COLUMN instance_version int NOT NULL DEFAULT -1 AFTER zone_id,
+DROP PRIMARY KEY,
+ADD PRIMARY KEY (character_id, zone_id, instance_version) USING BTREE;