As discussed this adds bundling of `.env` files in `serverless` mode so that the environment values are also available when deploying with this target closes: https://github.com/zeit/next.js/issues/13332
* Enable "paths" support by default * Enable NEXT_PUBLIC_ prefix exposing the variable globally Part of #11106
* Clean up env tests a bit * Fix NEXT_PUBLIC env values not being inlined Co-authored-by: Joe Haddad <joe.haddad@zeit.co>
