Add resource identifier prefix configuration

In the editor, add a suggestion which add a resource identifier to the identification section of the record. 

![image](https://cloud.githubusercontent.com/assets/1701393/5501152/28182f8c-8755-11e4-96f0-82a1fa723857.png)


![image](https://cloud.githubusercontent.com/assets/1701393/5501155/2e6f0a36-8755-11e4-8f5e-7deda48b89cd.png)


The identifier is built from the prefix (default http://localhost:8080/geonetwork/srv/metadata/) defined in the admin > configuration page and the record UUID.

![image](https://cloud.githubusercontent.com/assets/1701393/5501149/1ebbd196-8755-11e4-8c85-951b9027a5ac.png)



In the admin, a batch process allows to compute the identifier for a set of record.