bird config is not compatible with bird v2.

[basaran]

Hello,

We were doing a migration to a newer host (from Centos 7 to Rocky 8), and the configuration generated is missing the now required syntax.

Basically, now everything needs to be wrapped in ipv4 {} or ipv6 {} blocks, and the syntax for filters are also completely different (not included in the default config).

I can send a PR when I have sometime over the weekend if you like. We need add a check for the bird version and use a different template for pre 2 and post 2.