Skarmark ssl bugfixes

This fixes 4 SSL related bugs - 
https://bugzilla.redhat.com/show_bug.cgi?id=1112904
https://bugzilla.redhat.com/show_bug.cgi?id=1112905
https://bugzilla.redhat.com/show_bug.cgi?id=1112906
https://bugzilla.redhast.com/show_bug.cgi?id=1113590

I have entered bug ids in the commit messages, but they are purely for tracking purpose so that they get moved to on_qa after the build. The fixes for all the bugs are quite related, so it was hard to separate them out in different meaningful commits. 

Few key changes -
1. Updated bindings to do add CA SSL cert verification options to the ssl context and unit tests
2. Updated pulp-gen-ca-certificate to create SSL cert and key.
3. Added SSLCertificateFile and SSLCertificateKeyFile to pulp apache config and added ssl certificate location to server config.
4. Documentation changes and instructions on how to import ca certs to system trusted authorities.

Since our currently supported OSs - RHEL, Fedora and CentOS all have the same location for system ca certs directory , it can be hardcoded, but I added these as options here, so that if we want our admin and consumer conf to be able to configure the location or disable ssl ca validation, we can use these options.