* [files]: Add allow-hotplug stanza to interfaces files
- start interface <interface_name> when the kernel detects
a hotplug event from the interface
ref: https://www.debian.org/doc/manuals/debian-reference/ch05.en.html
* [interfaces]: Combine vlan_interfaces and lag_interfaces file and add allow-hotplug
1. Remove vlan_interfaces and lag_interfaces file and members in teamd.j2
2. Add all interfaces to /etc/network/interfaces file
3. Add allow-hotplug stanza
4. Add up <command> to automatically add interfaces to VLAN and LAG
5. Add unique_name filter to minigraph.py to remove duplicate interface names
6. Add brctl to base image
7. Update sonic-swss submodule
Signed-off-by: Shuotian Cheng <shuche@microsoft.com>
