This allows users to query for resource properties of hosts,
allowing them to be used in creating leases more effectively. Two new
API endpoints are added for hosts, ``/properties`` and
``/properties/<property_name>``, which allow for listing available
properties, and updating a property respectively. Properties can be
listed with detail, showing possible values and visibility. Admins can
list public and private properties.
A new database table is added ``resource_properties``, which stores
property names and resource types. Resource specific property tables
(e.g. ``computehost_extra_capabilities``) entries store a foreign key to
``resource_properties``, rather than the capability name.
Implements blueprint resource-properties-discovery-api
Change-Id: Ib9f1140c44c5e4fbef6e019c48a842869368cb21
f5e6d24826