Lua cpp expose

Exposition to Lua runtime mechanism proposition.

The user has to create an object that is LuaScriptAbleObject, make it inherit the CRTPLuaScriptObject class and voila.

For example, a simple FooBar examples might be:

// Default sample exposer for lua scripts
script_class (SampleObject) {
    LUA_SCRIPTABLE_CLASS(SampleObject)

    SampleObject()  noexcept { fprintf(stderr, "CREATE SampleObject\n"); }
    ~SampleObject() noexcept { fprintf(stderr, "DESTROY SampleObject\n"); }

    static int foo(lua_State *L) noexcept
    {
        SampleObject *obj = CHECK(L, 1);
        double bar        = luaL_checknumber(L, 2);
        return 0;
    }

    static constexpr inline auto metaMethods = { luaRegDefaultGC, LUA_DECL_CREATE(SampleObject) };
    static constexpr inline auto methods     = { LUA_DECL_METHOD(SampleObject, foo) };
};

A sample file for a script can be found at utils/lua/sample-spec.lua, this is just a proposition.