Add notifications to Sahara

Added following notifications to Sahara:
 * Notification about creating cluster
 * Notification about destroying cluster

Partially implement: blueprint ceilometer-integration

Change-Id: I7add0e477ab16f189c533857ad6a158ee41242de
Add notifications to Sahara

Added following notifications to Sahara:
 * Notification about creating cluster
 * Notification about destroying cluster

Partially implement: blueprint ceilometer-integration

Change-Id: I7add0e477ab16f189c533857ad6a158ee41242de