merge REST feature to GET all tasks belonging to a procedure

I integrated @cgiraldo new feature to better fit into the Spring configuration approach already used. 

Carlos approach is very good, but I decided to change access point to 

```
GET /tasks?procedureId=whateveryourprocedureidlookslike HTTP/1.1
```

This approach is filtering on a collection of tasks.

Independent to what approach we actually use, we should consider that accessing procedures' tasks may be a security/privacy issue. This however is only the case, if the SPS instance is deployed as a public service and provides sensible task information. However, the current implementation requires only login when adding SensorOfferings so one should carefully think about the environment the SPS is being used (for example being only accessible by clients via http://localhost or other internal IP)