Ports should not be hardcoded

[rlouapre]

They should default to the standard value but it should be possible to override them

https://github.com/ryanjdew/go-marklogic-go/blob/master/clients/managementClient.go#L17

[rlouapre]

One option would be to pass a struct connection

https://github.com/rlouapre/go-marklogic-go/blob/master/clients/adminClient_test.go#L16