Move LuaCommon.h's lua_push* functions to lua::

[Pirulax]

Moved all our custom userdata push stuff from LuaCommon to lua::. Eventually all lua_push should be replaced with lua::Push for code consistency reasons.

I originally didn't want to do the second commit in this PR, but I couldn't get it to compile otherwise (I got a ton of linker errors, probably should've moved #pragma once below the luaBasic include.)

Only review the first commit. The second commit is find and replace all basically. I've tested it. (Started freeroam resource and played a little). Doesn't require any in-depth review.