preliminary devices support

Signed-off-by: David Greaves <david.greaves@jollamobile.com>
Setup SDK LAN with both ethernet interfaces; do it before connman comes up but after shared folder

Signed-off-by: David Greaves <david.greaves@jollamobile.com>
Remove default unit. Setup correct [Install] sections

Signed-off-by: David Greaves <david.greaves@jollamobile.com>