Feature/ospf-api

ReadOSPFConfiguration exporting the OSPF configuration trough API. It returns the list of ospfAreas and every ProtocolEndpoint in all of them. Example:

```xml
<?xml version="1.0" encoding="UTF-8"?>
<ospfService>
   <ospfArea>
      <areaId>0</areaId>
      <ospfProtocolEndpoint>
         <name>ge-2/0/0.13</name>
         <enabledState>ENABLED</enabledState>
      </ospfProtocolEndpoint>
      <ospfProtocolEndpoint>
         <name>gr-1/1/0.1</name>
         <enabledState>ENABLED</enabledState>
      </ospfProtocolEndpoint>
      <ospfProtocolEndpoint>
         <name>gr-1/1/0.2</name>
         <enabledState>ENABLED</enabledState>
      </ospfProtocolEndpoint>
      <ospfProtocolEndpoint>
         <name>gr-1/1/0.3</name>
         <enabledState>ENABLED</enabledState>
      </ospfProtocolEndpoint>
   </ospfArea>
</ospfService>
```


Resolves issue [ http://jira.i2cat.net/browse/OPENNAAS-1263 ]