main.cc: remove scylla dns dependency
main.cc: remove scylla dns dependency

Use seastar facilities instead.

duarten/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla,avikivity/scylla,duarten/scylla,duarten/scylla,avikivity/scylla