First phase checkin for new format for vlan aware bridge

First phase checkin for new format for vlan aware bridge

Ticket: CM-3346
Reviewed By:
Testing Done: Sanity test + test new bridge format

There are a bunch of open issues with `vlan` interface handling.
Below is the format.

auto swp1
iface swp1
    bridge-access 300
    mstpctl-pathcost 0
    mstpctl-adminedge yes
    mstpctl-autoedge yes
    mstpctl-p2p yes
    mstpctl-bpduguard yes
    mstpctl-treeprio 64
    mstpctl-network yes
    mstpctl-bpdufilter yes

auto swp2
iface swp2
    bridge-vids 301
    bridge-pvid 302
    bridge-pathcost 10
    bridge-priority 10
    bridge-multicast-router 0
    bridge-multicast-fast-leave 1

auto br0
iface br0
    bridge-vlan-aware yes
    bridge-stp on
    bridge-ports swp1 swp2
    bridge-vids 2001

auto br0.2001
iface br0.2001
    address 10.0.14.2
    hwaddress 00:03:00:00:00:12
    address-virtual 00:00:5e:00:01:01 11.0.4.1/24

auto br0.2001
vlan br0.2001
    bridge-igmp-querier-src 172.16.101.1