Feature/network creation

This (huge) pull request introduces the network creation logic. 

The networkManagement capability receives a request containing the user desired network. The network logic consists of:

1. Creation of the new networkResource
2. Manual binding, so the method can access to his resource capabilities.
3. Check which resources the network will contain
4. Create slice for these resources, if they're sliceable.
5. Delegate request to underlaying network, if esxists.(still to be implemented)
6. Create internal port links.
7. Define network external ports.
8. Reserve all devices for specified period of time.

TODO: add resources to the network, so the IResourceProvider capability of the network contains them.