In the script's API `COMPANY_INVALID` has a value of -1, whereas the internal
game's `INVALID_COMPANY` has a value of 255. Since the script's API also has
a `COMPANY_SPECTATOR` with a value of 255, these enumerations cannot be easily
reconciled by casting. As such, replace all casts in the script API with
either ScriptCompany::FromScriptCompanyID or ScriptCompany::ToScriptCompanyID.
Also make clear whether CompanyID is ::CompanyID or ScriptCompany::CompanyID
by using either one of those over CompanyID in the script's API.
This was originally generic and used by YAPF, but now it is used only by script objects.
CCountedPtr provided much more (untested) functionality than used.
ScriptObjectRef already exists for script objects and does the same thing, so use this instead.
Otherwise some compilers, e.g. MSVC, do not pick up that these are temporaries
and as such it will pass the temporaries to `const std::string &` instead of
the wanted `std::string &&`
Command functions are those that call ScriptObject::Command, and functions
with company access are any that call ScriptObject::GetCompany. This is a bit
over-protective, but having the check everywhere makes it easier to validate
that no check is missing automatically instead of by review.