zebra: support for type-0 ESI

zebra: support for type-0 ESI

Earlier type-3 ESI was the only format supported for evpn-mh. Updated the
CLI to allow a 10-byte type-0 ESI.

Both type-0 and type-3 ESIs are statically configured; just in two different
ways -
1. type-0 is configured as a complete 10-byte string
2. type-3 is configured as a 6-byte es-sys-mac and a 3-byte
local-discriminator.

Sample config -
!
interface hostbond1
 evpn mh es-id 00:44:38:39:ff:ff:01:00:00:01
!

This is a CLI-only change and has no functional impact.

Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>