Death to objtype

[zach2good]

When using a type-erased entity (CBaseEntity, CBattleEntity, or any entity in Lua) there is a lot of checking to find out "are you a mob, are you a character" etc. before additional logic is applied to them.

We have two mechanisms for this:

auto* entityPtr = ...; // From somewhere
if (const auto* PChar = dynamic_cast<CCharEntity*>(entityPtr))
{
    // Use PChar as you'd like
}

and

auto* entityPtr = ...; // From somewhere
if (entityPtr && entityPtr->objtype == TYPE_CHAR)
{
    const auto* PChar = static_cast<CCharEntity*>(entityPtr);
    // Use PChar as you'd like
}

These are equivalent, but the objtype-based method is a lot more verbose and leaves a lot of room for people to skip a nullptr check, just go straight for the static_cast or a C-style cast, etc.

My proposal is to remove objtype from CBaseEntity and enforce the use of dynamic_cast everywhere where we're trying to determine what an entity is.

This will also be reflected in Lua where we won't check like this: caster:getObjType() == xi.objType.PC, but we'll just use a helper of: caster:isPC()