Added classes to manage repositories for yum

* manage all base repositories
  * manage epel if required
  * cleanup /etc/yum.repos.d directory

hiera.yaml

@@ -6,5 +6,9 @@ defaults:
 hierarchy:
   - name: Node-specific data
     path: "nodes/%{trusted.certname}.yaml"
+  - name: "Per-OS & Release Specific Data"
+    path: "os/%{facts.os.name}/%{facts.os.name}%{facts.os.release.major}.yaml"
+  - name: "Per-OS Specific Data"
+    path: "os/%{facts.os.name}/all_releases.yaml"
   - name: Common data shared across nodes
     path: "common.yaml"