fix(sys-apps/baselayout): Assorted cleanups/fixes

- Add || die to commands without them to avoid missing errors.
- Symlink resolv.conf to /run on amd64-generic images again.
- Properly sed /etc/issue out of tmpfiles.
- Fix symlinks for mtab and sudo.
- Fix directory ordering in tmpfiles.
- Update groups, a few were missing or incorrect.
- Bump coreos-base/coreos revision.