Maximise cardano-api GHCJS compatibility

- By not using the network library in cardano-api we improve GHCJS
  compatibility (see ghcjs/ghcjs#305).

Author: sevanspowell

cardano-api/cardano-api.cabal

@@ -127,7 +127,6 @@ library
                       , formatting
                       , iproute
                       , memory
-                      , network
                       , nothunks
                       , optparse-applicative-fork
                       , ouroboros-consensus

cardano-api/src/Cardano/Api/Certificate.hs

@@ -42,13 +42,13 @@ import           Data.ByteString (ByteString)
 import qualified Data.Foldable as Foldable
 import qualified Data.Map.Strict as Map
 import           Data.Maybe
+import           Data.Word (Word16)
 import qualified Data.Sequence.Strict as Seq
 import qualified Data.Set as Set
 import           Data.Text (Text)
 import qualified Data.Text.Encoding as Text
 
 import           Data.IP (IPv4, IPv6)
-import           Network.Socket (PortNumber)
 
 import qualified Cardano.Crypto.Hash.Class as Crypto
 import           Cardano.Slotting.Slot (EpochNo (..))
@@ -160,11 +160,11 @@ data StakePoolRelay =
 
        -- | One or both of IPv4 & IPv6
        StakePoolRelayIp
-          (Maybe IPv4) (Maybe IPv6) (Maybe PortNumber)
+          (Maybe IPv4) (Maybe IPv6) (Maybe Word16)
 
        -- | An DNS name pointing to a @A@ or @AAAA@ record.
      | StakePoolRelayDnsARecord
-          ByteString (Maybe PortNumber)
+          ByteString (Maybe Word16)
 
        -- | A DNS name pointing to a @SRV@ record.
      | StakePoolRelayDnsSrvRecord