Added support for channel binding tokens when using HTTPS connections

[jborean93]

Currently if a WSMan target has set Auth/CbtHardeningLevel = Strict then OMI will fail to connect over HTTPS when using Negotiate/Kerberos. This is because the current code does not pass in the necessary structure to GSSAPI that binds the auth with the TLS channel that the CBT check is for.

This PR retrieves the CBT data for GSSAPI if possible and makes sure it's passed into gss_init_sec_context if available. It also rejigs some of the SSL connection code in preparation for cert verification that I'm hoping to look into next.

TODO:

• [x] Add Integration tests (I think this will fail due to MIT bug when SPNEGO didn't pass along the CBT info until 1.18.2 - https://github.com/krb5/krb5/commit/d16325a24c34ec9a5f6fb4910987f162e0d4d9cd)
  • [x] Integration tests with Kerberos
  • [x] Integration tests with NTLM
  • [x] SHA1 cert
  • [x] SHA256 cert
  • [x] SHA384 cert
  • [x] SHA512 cert
  • [x] RSASSA-PSS
• [x] Test on macOS
• [x] Add docs on this functionality and the limitations