Feature Request: Warn instead of fail in case of a resolve error

[margau]

Currently, if a resolve() fails, the ferm process/service fails completely.
In my use case, I sometimes forget to update the configuration etc, leading to an NXDOMAIN. This should not lead to the firewall failing completely, but only lead to the rule being applied without the IP.
I'm not sure if a change of the default configuration would be sufficient, but at least a parameter like "tolerant=true" in the resolve method would be helpful, which simply ignores failed domain names.