setup-environment: append path to conf/local.conf.append{,.$MACHINE}

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
mel.conf: move minnow bits to lconf append

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
Drop setup-env-local-append-minnow.conf

Signed-off-by: Christopher Larson <chris_larson@mentor.com>