* ZTP infrastructure changes to support DHCP discovery provisioning data
- Dynamically generate DHCP client configuration based on current ZTP state
- Added support to request and process hostname when using DHCPv6
- Do not process graphservice url dhcp option if ZTP is enabled, ZTP service
will process it
- Generate /e/n/i file with all active interfaces seeking address assignment
via DHCP. Only interfaces that are created in Linux will be added to /e/n/i.
Also DHCP is started only on linked up in-band interfaces.
Signed-off-by: Rajendra Dendukuri <rajendra.dendukuri@broadcom.com>