Allow specifying multiple PrefixLists and CommunityLists

[patschi]

Fixes #3074

For me unclear reasons PrefixLists and CommunityLists did not allow to specify multiple lists. Saving them failed with a very unclear error Related item not found in the UI, as pointed out in above issue.

The bgpd.conf does include support specifying multiple lists, but the UI blocked the same: https://github.com/opnsense/plugins/blob/4546aeb47d62010ea4f8d3e4204b26285be864fe/net/frr/src/opnsense/service/templates/OPNsense/Quagga/bgpd.conf#L180-L218

After this change, multiple lists can be selected and saved:

And:

After reloading the service, the config at /usr/local/etc/frr/bgpd.conf reflects the change:

ip prefix-list AllowAll seq 99 permit any
!
ip prefix-list DenyWAN seq 20 deny SOME_IP/24
!
!
!
!
route-map DefaultRouteMap permit 20
 match ip address prefix-list AllowAll
 match ip address prefix-list DenyWAN