network_interfaces: use allow-ovs for OVSBridge

network_interfaces: use allow-ovs for OVSBridge

new openvswitch-switch service use "ifup --allow-ovs",
and this race with "auto ..." used by networking service

bug reported here:
https://forum.proxmox.com/threads/so-is-openvswitch-bonding-just-broken-on-pve-6-whats-going-on.58020/

This is also fixing ovs with ifupdown2

Openvswitch github have a note about this:
https://github.com/openvswitch/ovs/commit/e0dfd67b456c8ea36cc2e2f23039a300dbbedfed#diff-555e6da95251766b76e83867900bd8fe

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>