Create Polymorphic VI for the Create/Destroy VIs

[volks73]

The Known Hosts, Session, and SFTP classes have the Create and Destroy VIs, just like all other classes in the toolkit. However, unlike all other Create and Destroy VIs, these versions are not polymorphic. Just to be on the extreme end of consistent, even though there is (currently) only one variant, the Known Hosts, Session, and SFTP Create and Destroy VIs should be changed to polymorphic VIs.

Note, the Agent and Listener classes only have a single instance for its Create and Destroy VIs but these are polymorphic.

[volks73]

The Create and Destroy VIs are changed to polymorphic VIs for the Known Hosts, Session, and SFTP classes as of 63ceb92.