This means people have to alter files less and things canbe scripted more.

This code was altered from PS1 of
I7b8d651d656f7f254506df0900d84a173f27880a which maintained the
.env file in a user config dir instead of within the mediawiki core
dir.
However for now a minimal change is to just alter this file in place
within the mw core dir.

Change-Id: I7b8d651d656f7f254506df0900d84a173f27880a