Elytron key/trust-manager-factory default algorithm

key-manager-factory and trust-manager-factory requires user to specify algorithm.

Consider defaulting in elytron code to TrustManagerFactory.getDefaultAlgorithm() and KeyManagerFactory.getDefaultAlgorithm().
It is java portable as for oracle java it returns SunX509 and for Ibm java IbmX509.

This JIRA is in scope of "user experience", minimizing necessary user input configuration.

David: "The trust manager definitely should use the default algorithm when none is given; in this case the algorithm name isn't an "algorithm" per se, it's just an implementation name."