Network interruption during interfaces configuration - solved

First tentative to maintein connection under "if $_external_device" statement

Descrizione delle modifiche fin qui fatte
- files/heat-keystone-setup-domain
-- fix dell'import di oslo.config
- manifests/profile/database-client.pp
-- classe per l'installazione del mysql-client in locale; in sostituzione della classe manifests/profile/database.pp
- manifests/profile/keystone.pp; manifests/resources/database.pp
-- modifiche al file keystone.conf

- Modifiche alle altre classi per staccare Rabbit-MQ, CEPH, Percona, HAproxy, keepalived dalla configurazione dell'infrastruttura.

Neutron DHCP Agent now passes a MTU (1438 by default) to instances to make Neutron networks working on a physical network swhich don't allow jumboframes

Fixed neutron-vpn-agent service conflict with neutron-l3-agent service & added some mandatory sysctl parameters

- Network configuration (such as IP addresses, default gateway...) shall now be set up beforehand. It is not done by the base class anymore. We now simply use the IPs from configured interfaces.
- Reworked +Fixed some things in Neutron networking services too.

Added/Fixed Neutron services for server/router/client. The router works well even when we only have one NIC