added contacts, extended navbar

Aggiunta sezione Contacts in navbar. Aggiunta telegrafica lista con contatti ufficiali.

src/contacts/index.en.md

+title: Contacts
+----
+
+Official Contacts
+=================
+
+We use these accounts to send out updates: 
+(**but don't try get in contact with us here, publishing is automated and the accounts unattended**): 
+
+* Our official [Blog](https://cavallette.noblogs.org/)
+* Our official [Twitter Account](https://twitter.com/cavallette)
+
+If you need to get in contact with us in person, you can:
+
+* Join the #ai channel on our [IRC server](https://www.autistici.org/docs/irc/)
+* If you encounter technical problems, write to [helpdesk](mailto:help@autistici.org).
+* For legal contacts, write to [Associazione AI-ODV](mailto:associazione@ai-odv.org). 
+* Other issues should be addressed to our [e-mail contact](mailto:info@autistici.org).