sdk: initialize home directory when creating a new chroot
sdk: initialize home directory when creating a new chroot

To match the behavior of make_chroot.sh we now drop in bash dot files,
taking care to remove symlinks to the CoreOS provided dot files in /usr.

marineam/mantle,mjg59/mantle,dm0-/mantle,glevand/coreos--mantle,mjg59/mantle,mischief/mantle,dm0-/mantle,quantum/coreos-mantle,mischief/mantle,marineam/mantle,quantum/coreos-mantle,glevand/coreos--mantle