Add NATS and mongodb to the skip protocols list

[grampelberg]

There needs to be a little bit more thought on where this will end up.

[olix0r]

Are there IANA registrations for these ports? Or are they sufficiently unique that they are not likely to collide with other applications?

[olix0r]

https://docs.mongodb.com/manual/reference/default-mongodb-port/ uses fairly high-numbered, less common ports.

NATS default appears 4222 (not IANA registered), which is more in the domain of ports likely to be claimed by other applications. But NATS may be common enough to warrant this potential breakage?

[grampelberg]

I'm content documenting it so that we have somewhere to point confused folks to. I don't think it is worth adding to the proxy/control plane.