Feature/create resource reuse descriptor with different name

* Specify resource name using resource:create CLI command
* Fixes in resource:create CLI command output
   * It now reports correct number of created resources
   * It now warns the user when number of created resources differs from requested one 
   * It now correctly displays file url when it does not exists

Following snippet illustrates current command output:

```
OpenNaaS>resource:create /path/to/myresource.descriptor /path/to/myresource.descriptor /path/to/unexisting.descriptor
[INFO] Loaded descriptor at file:////path/to/myresource.descriptor
[INFO] Loaded descriptor at file:////path/to/myresource.descriptor
[ERROR] File not found: /path/to/unexisting.descriptor (El fitxer o directori no existeix)
[INFO] Created resource router:myresource
[ERROR] There is already a resource in this respository with this name: myresource
[WARN] Created 1 resource/s of 3
```
Following snippet illustrates how to specify the name:
```
OpenNaaS>resource:create -n AAA -n BBB /path/to/myresource.descriptor /path/to/myresource.descriptor
[INFO] Loaded descriptor at file:////path/to/myresource.descriptor
[INFO] Loaded descriptor at file:////path/to/myresource.descriptor
[INFO] Created resource router:AAA
[INFO] Created resource router:BBB
[INFO] Created 2 resource/s of 2
```