Remove --port and update --publish for services to support syntaxes

Add support for simple and complex syntax to `--publish` through the
use of `PortOpt`.

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

command/service/update_test.go

@@ -364,6 +364,7 @@ func TestUpdatePortsRmWithProtocol(t *testing.T) {
 	assert.Equal(t, portConfigs[0].TargetPort, uint32(82))
 }
 
+// FIXME(vdemeester) port to opts.PortOpt
 func TestValidatePort(t *testing.T) {
 	validPorts := []string{"80/tcp", "80", "80/udp"}
 	invalidPorts := map[string]string{