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

Fixed various timeout values, keep-alive parameters & "backup" option for HAProxy - Galera to avoid unexpected socket closes, failed SQL transactions, etc.

- 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.

Removed database_idle_timeout as it is not necessary anymore since 6f05de06 and updated two HAProxy IP addresses

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

Small fixes such as hiera.yaml link, variable renaming and Neutron missing class / wrong default password

Added Keystone, Glance, Cinder, Nova, Neutron API services & Added Galera/RabbitMQ to Load-Balancing.
(The commit is pretty big, sorry about that, I'm still bootstrapping the project)