Cloned from launchpad blueprint https://blueprints.launchpad.net/nova/+spec/nova-oslo-scheduler.

Description:

Now in oslo, we already put some scheduler filters/weights logic there and cinder is using oslo scheduler filters/weights logic, seems we want both nova&cinder use this logic in future.

It is better to enable nova use filter/weight logic from oslo and also use entry point to handle all filters/weight logic.

We can first sync from oslo with following filteres/weights:
1) availablity_zone_filter.py
2) capabilities_filter.py
3) extra_specs_ops.py
4) json_filter.py
5) retry_filter.py
6) base_filter.py
7) base_handle.py
8) base_weight.py

The last work item is enable nova use entry point to handle scheduler filters/weights.

Specification URL (additional information):

None