Support for Rendering lua.LValue as Lua Source Code Literals

[kmirzavaziri]

It would be super helpful to have a way to convert lua.LValue into a Lua source code string that represents the literal value. In our current setup, we need to send Lua configuration alongside scripts to the front end, so they can execute the same logic. However, GopherLua doesn't provide an easy way to achieve this right now. Currently we're using a custom function that takes lua.LValue and renders it, it's good to have such function natively available in gopher lua.