**What type of PR is this?**
/kind cleanup
**What this PR does / why we need it**:
Staging the GCE Cloud Provider as part of KEP [20190125-removing-in-tree-providers](https://github.com/kubernetes/enhancements/blob/master/keps/sig-cloud-provider/20190125-removing-in-tree-providers.md). Staging repo setup here https://github.com/kubernetes/legacy-cloud-providers
Moves the GCE cloud provider implementation to staging.
This is in preparation for moving the cloud provider code out of tree entirely.
However we need it in staging while the code needs to be consumed both in/out of tree.
**Which issue(s) this PR fixes**:
Fixes #
**Special notes for your reviewer**:
**Does this PR introduce a user-facing change?**:
```
NONE
```
Updated import dependency tracking.
Factored in the cleanup from #77412
Minor fix to go.mod.
This commit adds logic for allocating and associating a public IP, if the `—load-balancer-ip` option is not used. It will do proper management of IP’s that are allocated by this provider, so IP’s that are no longer needed/used will also be released again.
Additionally the provider can now also work with CloudStack projects and advanced (VPC) networks.
Lastly the Zone interface now returns an actual zone (supplied by the cloud config), a few logical errors are fixed and the first few tests are added.
All the functionality is extensively tested against both basic and advanced (VPC) networks.
When vSphere cloud provider object is instantiated, the VM name of the
Node where this object is being create in needs to be set. This patch
also includes vSphere as part of the cloud provider package.
