Core/BattlePets: some work

[soulfrost]

add some BattlePetStates

[horn]

I haven't decided yet whether we really need full states enum or not, most of them will be set by generic abilities code (like states[id] = value;), apart from that it's ok, thank you. Btw here are some other species and journal flags ChipLeo/SkyFire_5xx@78182c5#diff-5bc25c940945ccd7ac176e0e5736f606R23

[soulfrost]

so - remove states and update flags in pr, ye?
also, what are u think about using enum class : smthng like this

enum class BattlePetSpeciesFlags : uint16
{
     CANT_TRADE             = 0x010,
     UNOBTAINABLE           = 0x020,
}

    if (BattlePetSpeciesEntry const* speciesEntry = sBattlePetSpeciesStore.LookupEntry(pet->JournalInfo.CreatureID))
         if (speciesEntry->Flags & BattlePetSpeciesFlags::CANT_TRADE)
             return;