Update .env + example to default to production and debug off

[cln-io]

By default we should be on production, users can switch it to debug if they want, but users will just dump this download/install into their webservers so lets stick to safe defaults

[JulianPrieber]

I think we want to have debugging enabled during the installation. Maybe disable it after the installation has completed?

[cln-io]

Fair remark, I'm approaching this from a set&forget situation, people take this project deploy it and never look back at it.

I would keep the env -> debug off, and production, but during setup maybe override it in the php files/session?