Detect BIRD without IPv6 support

[mceyran]

e.g. ignore incoming IPv6 ROA records from RTR server after "9001 This is an IPv4 router, therefore IPv6 addresses are not supported" is received from BIRD.

[remcovanmook]

With the latest merge, you can now use a command line option to tell which IP version updates to send to Bird. Even though it's not detecting automatically (in theory that could be built) this should solve this issue for most use cases. (-v 4 | -v 6 | -v 46)

[waehlisch]

Partially fixed in 498e554