* Removed global realm variable from World and use RealmList everywhere
* Match auth build key with client version
* Restored allowedSecurityLevel checks for realmlist packet building
* Restored updating population field, mysteriously removed 15 years ago in f20b25d1c9
* Added script for "Summon Battle Pet" spell (118301).
* Set the saved display of the battle pet when summoning it.
* If a summon has SummonPropertiesFlags::SummonFromBattlePetJournal it will remove NpcFlag UNIT_NPC_FLAG_WILD_BATTLE_PET (Wild battle pets).
* When a creature is summoned with SummonTitle::Companion, it will check to see if it has SummonPropertiesFlags::SummonFromBattlePetJournal before updating the battle pet's update fields. (If you have a summoned battle pet and summon a creature with that SummonTitle, it will incorrectly update the battle pet's update fields with the summoned battle pet's data).
* Implemented SummonPropertiesFlags::UseCreatureLevel. If a summon has this flag, it will use the owner's level (If the summon doesn't have SummonProperties it will always use the selected level).
* Add pet when learning it for the first time (summon spell not known).
* Removed code that adds battle pet if its summon spell is known (Learn cageable pet -> Cage pet -> Log out -> Log in -> Pet is added).
* When uncaging check that the species has a summon spell before trying to learn it.
* Rename WorldPackets::BattlePet::BattlePet::CollarID to WorldPackets::BattlePet::BattlePet::DisplayID
* Use the DisplayID field to store the model of the battle pet. If the species has BattlePetSpeciesFlags::RandomDisplay, nothing is stored. Otherwise a random model is chosen from those available
* Stored DisplayID in ITEM_MODIFIER_BATTLE_PET_DISPLAY_ID when caging the battle pet (previously the CreatureID was being stored)
* Modified SendPlaySpellVisual function to allow sending Target and TargetPosition at the same time
* Added SpellVisual when uncaging
* Define BattlePetBreedQuality enum class.
* Check the quality of the battle pet species in battle_pet_quality table to avoid invalid values.
* Set CurrentBattlePetBreedQuality and WildBattlePetLevel update fields with the data of the summoned battle pet.
* Added function to calculate the WildBattlePetLevel of wild battle pets according to their spawn zone.
* Define BattlePetSpeciesFlags enum class.
* Define BattlePetDbFlags enum class.
* Added check to prevent the pet from being caged if its species has flag BattlePetSpeciesFlags::NotTradable.
* Added check to prevent the pet from being caged if it's in battle pet slots.
* Added check to prevent the pet from being caged if its health is below maximum health.
* Only add pet if the species has flag BattlePetSpeciesFlags::WellKnown.
* Added function to check flag BattlePetSpeciesFlags::LegacyAccountUnique to avoid learning copies of unique pets.
* Implemented CMSG_BATTLE_PET_CLEAR_FANFARE.
* Fixed caged pet item chat message
* BattlePetMgr optimizations: removed copying data all over the place
* Fixed gaining two pets when learned from item for the first time
* Fixed dismiss button
* Mostly aimed at removing Log/DatabaseEnv includes from other headers
* Fix most packet headers including other packet headers - moved common structures such as ItemInstance to their own files
* Moved SAI function definitions to source files (massive or requiring many different dependencies)
* Extracted base CriteriaHandler class that deals with criteria only and will be reused for future scenario implementation
* Fixed players earning guild achievements
