Introduces a keepalived manager for HA

This patch introduces a keepalived manager
which will be used for the blueprint
blueprint l3-high-availability.

The manager can create a keepalived.conf compliant configuration,
start, stop and restart the service, as well as create keepalived
notification scripts.

Implements: blueprint l3-high-availability
Change-Id: I1ba9f332778f27de950d9e97d4fb4a337f6f26da
Co-Authored-By: Assaf Muller <amuller@redhat.com>
Apic drivers enhancements (second approach): Sync

    - Model synchronization

Implements blueprint: apic-driver-enhancements

Change-Id: I4264afe5c140c3576951c1a5a28a8d7666481147
Merge "Introduces a keepalived manager for HA"
Merge "Apic drivers enhancements (second approach): Sync"