Added 'Configuring Certificates' section OpenId README (#845)
Added 'Configuring Certificates' section OpenId README (#845)

* #827 Added Configuring Certificates section OpenId README

* #827 Further updates to OpenId README following reviews

OrchardCMS/Brochard,lukaskabrt/Orchard2,lukaskabrt/Orchard2,xkproject/Orchard2,stevetayloruk/Orchard2,stevetayloruk/Orchard2,stevetayloruk/Orchard2,stevetayloruk/Orchard2,petedavis/Orchard2,xkproject/Orchard2,lukaskabrt/Orchard2,OrchardCMS/Brochard,xkproject/Orchard2,stevetayloruk/Orchard2,petedavis/Orchard2,petedavis/Orchard2,petedavis/Orchard2,xkproject/Orchard2,OrchardCMS/Brochard,xkproject/Orchard2,lukaskabrt/Orchard2