Add promise version of getPorts function

[MasterOdin]

PR adds a new getPortsPromise function to allow using a promisified version of getPorts, similar to how there's a getPortPromise version of getPort. A test is included for the function, which mimics what I saw for testing getPortPromise.

I also fixed a type error which made it seem like the options parameter was required for getPorts, where it's optional, just need to always pass the count and callback.