Add force_nodes to filter properties

Add support for "force_nodes" to filter properties, following the example
of force_hosts. In doing so, fix an issue where the presence of either
force_hosts or ignore_hosts would have squashed a host with multiple nodes.

A node can be passed in via the --availability_zone
option, separated from the hostname with a colon. Eg,
  nova boot --availability_zone=zone:host:node
Note that "host" is optional here, and "zone::node" also works.

DocImpact

Implements bp baremetal-force-node

Change-Id: Icfee63c80eb355c29594f8badde4183496b395ac
Deprecate show_host_resources() in scheduler manager

This method does not at all belong in the scheduler. Its only use is
from being remotely called by nova-manage to whom it returns data
fetched from the db. I think nova-manage is better of fetching this
data on its own instead of making this extra round trip to the
scheduler.

Change-Id: I435300cdd15bdd041cbe5718ae064b98cec4cceb
Merge "Deprecate show_host_resources() in scheduler manager"
Merge "Add force_nodes to filter properties"