"Fixes #1531
Adds lookup to gms::inet_address and uses it in (hopefully all) the
salient places where configured symbolic names are interpreted.
Removes the dummy dns modula in scylla in favour of the seastar one."
* 'calle/use-dns' of github.com:cloudius-systems/seastar-dev:
remove scylla dns code
service::storage_service: Remove depedency on scylla dns
main.cc: remove scylla dns dependency
main/init: Lookup inet addresses from config by dns lookup
db::system_keyspace: Find rpc_address by lookup
gms::inet_address: Add lookup functionality.
scylla tls: Add option support for client auth and tls opts