Implements filters and schedules in nova.cfg

Adding filters and scheduling parameters to nova.cfg for better to reach
more smooth VM distribution across non-homogeneous compute nodes.

Backport to stable/4.1 includes follow-up fix from:
Idb3dbb6fddb18c06759e483731b971a1be953583.

Change-Id: I59a49c613da29eda04eec7dfe911d8fc31380a33
Implements: blueprint scheduler-config-improvements
Closes-Bug: 1300027