add recipe manage_by_attributes

Retrieve search keys from attributes "certificate".  
Set ID and LWRP attributes to node attribute following...

    "certificate": [
      {"self": null},
      {"mail": {
        "cert_path": "/etc/postfix/ssl",
         "owner": "postfix",
         "group": "postfix"
        }
      },
    ]


and a little change to metadata.
    FC045: Consider setting cookbook name in metadata: ./metadata.rb:1