fix(coreos-base/coreos-base): Remove nsswitch.conf

Provided by glibc now that it is being installed properly.
fix(profiles): Move default INSTALL_MASK to profiles.

The INSTALL_MASK is altered all over the place, clean it up by moving
all of it to profiles. Add /usr/share/{i18n,locales} to exclude those
installed by glibc since it doesn't have a nls use flag to disable them.
fix(profiles): Move INSTALL_MASK from common.sh to profiles.

This one isn't used by default, only when building final images like so:

    export INSTALL_MASK=$(portageq-$BOARD envvar PROD_INSTALL_MASK)
Merge pull request #267 from marineam/turtle-chain

Turtle chain