api-ref: POST /resource_providers/{uuid}/inventories is missing

[Matt Riedemann]

https://developer.openstack.org/api-ref/placement/#resource-provider-inventories

Is missing POST /resource_providers/{uuid}/inventories, which is implemented:

https://github.com/openstack/nova/blob/64635ad4a5f60a79e1ec2d5369a8f84bfeccb7e4/nova/api/openstack/placement/handler.py#L84

https://github.com/openstack/nova/blob/64635ad4a5f60a79e1ec2d5369a8f84bfeccb7e4/nova/api/openstack/placement/handlers/inventory.py#L205

resource_class and total are required in the request, resource_provider_generation is not.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/511342

[OpenStack Infra (hudson-openstack)]

Change abandoned by Hongbin Lu (<email address hidden>) on branch: master
Review: https://review.openstack.org/511342

[Takashi Natsume (natsume-takashi)]

In https://review.openstack.org/#/c/512215/, Jay said:

> The POST /resource_providers/{uuid}/inventories API call should not be documented IMHO. It does not have a correct response value (missing any indication of the resource_class that was created and it is not compatible with the dict-style return from PUT /resource_providers/{uuid}/inventories.
>
> We do not actually call POST /resource_providers/{uuid}/inventories anyway in the codebase outside of tests. Instead, we only use the PUT /resource_providers/{uuid}/inventories call, which I think is more appropriate and cleaner. I'd prefer to just remove the single-item POST /resource_providers/{uuid}/inventories endpoint entirely.