CASC-231 HttpsURLConnectonFactory is Not Serializable

Problem: THe HttpsURLConnectionFactory is not serializable, causing problems for clients that must serialize
the principal (which depends on a ProxyRetriever).

Solution: Make the HttpsURLConnectionFactory serializable.

QA Notes: added unit test to confirm serialize-deserialize
I'm guessing that if there was a collision, attempting to do auto-complete within the IDE would resolve the issue and make it explicit.

I'm also guessing that IntelliJ decides that after a certain number of imports it will make them a "*" (I'd have to look at the settings)