Refactor some misuse of RwLock fields on the butterfly Server struct
Refactor some misuse of RwLock fields on the butterfly Server struct

- Remove unnecessary Arc<RwLock<_>> around SocketAddr fields that were never
  mutated

- Change read-only block_list access to use RwLock::read, not ::write

- Return SocketAddr references rather than owned values to avoid cloning

- Make swim_port() and gossip_port() private

Signed-off-by: Jon Bauman <e6c6a4db54ad11b4de69fed67139594b59f3444f@users.noreply.github.com>

rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,habitat-sh/habitat,rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,habitat-sh/habitat,rsertelon/habitat