Environment variable files are now .env_setup.sh or .env_setup.bat
instead of .env_setup.bat and .setup.sh.
Change-Id: Ia192c6355d1c37237637e527e35f840e8c4ec88d
Move bootstrap.sh to root and create root symlink activate.sh
(pointing to bootstrap.sh).
Create symlinks to these files from inside pw_env_setup (to be
removed once recipes are updated).
Change-Id: I163d726402dd543d13b28cd5c7d066841dd93138