Verify X509 properties of trusted certificates

This should resolve https://github.com/opscode/chef/issues/1944.

I'd like to specifically request a good look at the documentation on generating certificates/self-signed certificates/subjectAltNames from @opscode/client-engineers 

@jamescott How can I leave a note for you to let me know when certain documentation has been published to the docs site?
Let's see if we can have James write something up and link to our own docs site.