Prepare for CiviCRM 5.0 release
Created by: seancolsen
This PR generalizes the language here so that all references to CiviCRM 4.7 apply equally to CiviCRM 5.0. I think it should be okay to merge now since it dosen't mention 5.0 explicitly. As well, I think that once 5.0 is released, we shouldn't need to make any more changes to the Sysadmin Guide.