Add FQDN name to "pjsip show srv_lookups" CLI command, REF 15305

It fixes the issue described in https://project.iopsys.eu/issues/15305#note-17 : The "Domain" name is defined as follows in TR104i2, "The domain name of the target host". In the competitors dmcli dump, the value of the FQDN that maps to the IP is listed, in our case it is always the SIP domain, name (which is the same everywhere). Relevant MRs: asterisk-chan-voicemngr!111 (merged) tr104!138 (merged)