Provide Documentation for CrowdCert and CrowdSSLVerifyPeer Directives

Integrating Crowd and Apache through SSL include configuring some directives that are not documented very well, for example CrowdCertPath and CrowdSSLVerifyPeer.

Since Crowd administrators doesn't have the guide necessary to help them on this, they need to make some guess and assumption to successfully configure Apache Crowd integration which will waste their time and effort.