[neutron] Approach to a spec for OVN BGP integration (RFE 2111276)

Hello, Jakub, Thank you for filing the RFE for Neutron support for OVN native support for route exchange, which includes BGP. We appear to have a common goal of making use of this with OpenStack, and we have time set aside this cycle to work towards this goal. Communication through IRC and e-mail often has limited bandwidth, and I wonder if you would be interested in participating in a A/V sync on some cadence to get us off the ground with the initial spec work. We have good experience with how the core OVN A/V sync is organized and we could do something similar for this. WDYT? -- Frode Nordahl