Add --winrm-authentication-protocol option 

@adamedx @NimishaS 

--winrm-authentication-protocol option has [basic, negotiate, kerberos] values. 
On windows --winrm-authentication-protocol = 'negotiate' applies 'winrm-s' monkey patch to do encrypted winrm communication.

Need to say the default here. I'd say that the default should depend on the transport -- for ssl, the default should be negotiate. For plaintext, it can be basic (for now) to avoid compatibility issues.