Merge pull request #52855 from NickrenREN/remove-rackspace

Automatic merge from submit-queue (batch tested with PRs 52880, 52855, 52761, 52885, 52929). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>..

Remove cloud provider rackspace

**What this PR does / why we need it**:
For now, we have to implement functions in both `rackspace` and `openstack` packages if we want to add function for cinder, for example [resize for cinder](https://github.com/kubernetes/kubernetes/pull/51498).  Since openstack has implemented all the functions rackspace has,  and rackspace is considered deprecated for a long time, [rackspace deprecated](https://github.com/rackspace/gophercloud/issues/592) ,
after talking with @mikedanese  and @jamiehannaford offline ,  i sent this PR to remove `rackspace` in favor of `openstack`

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #52854

**Special notes for your reviewer**:

**Release note**:
```release-note
The Rackspace cloud provider has been removed after a long deprecation period. It was deprecated because it duplicates a lot of the OpenStack logic and can no longer be maintained. Please use the OpenStack cloud provider instead.
```

hack/.golint_failures

@@ -153,7 +153,6 @@ pkg/cloudprovider/providers/gce
 pkg/cloudprovider/providers/openstack
 pkg/cloudprovider/providers/ovirt
 pkg/cloudprovider/providers/photon
-pkg/cloudprovider/providers/rackspace
 pkg/cloudprovider/providers/vsphere
 pkg/controller
 pkg/controller/bootstrap