Rt l2 vlan setup

This change updates the vlanconf to accept --translated-vlan-id as one of the parameters to configure vlan translation. Also update handling of vlans to be better aligned with vlan scenarios specifically to not overwrite the p-bit in traffic bridged from LAN.

This will have a positive impact of QoS as well since the header is constructed on ingress and hence p-bit to queue mapping is easier plus can be independently configured for each vlan port. Infact, p-bit rewrite can also be very easily built on this chance.