* nxos_bgp_neighbor: Add bfd support
- Add support for bfd state in nxos_bgp_neighbor
- Feature Pull Request
- nxos_bgp_neighbor
- Tested on platforms: `N3K,N6K,N7K,N9K`
* bfd T/F now bfd enable/disable
* pep fix ws
* nxos_bgp_neighbor_af does not want required_together
* fixup tests
* Fix max_prefix_* issues
* Require address-family
* Fix idempotency for next_hop_third_party
* Fix idempotency for allowas_in*
* Fix idempotency for *_in and *_out
* Reorder command generation again
`default` is first, then `max-prefix`, then booleans