Start implementing new requirements

Remove `Person_acts_for_Legal_Entity`.
Cosmetic fix: set ui_name for 'desc' attributes to 'Description'.
Rename `cool_down` attribute of `IP_Network` to `expiration_date`.
Add `name` to `Net_Interface_in_IP_Network`.
Fix regression tests.
Make Funkfeuer Vienna converter run again, Interface names are now the
name from the spider run if available, the name from redeemer else. The
Redeemer device names are used for the Net_Interface_in_IP_Network.
`Node` is no longer derived from `Subject`.
Add `PAP.Adhoc_Group` and `PAP.Person_in_Group`.
Vienna converter now adds persons to legal entities.
Add `node` to `IP_Network`
Add network import

Also add --anonymize option to get better turnaround times. Inserting
person info takes ages.