Automatic merge from submit-queue

VSphere cloud provider code refactoring

The current PR tracks the vSphere Cloud Provider code refactoring which includes the following changes.
- VCLib Package - A framework used by vSphere cloud provider for managing the vSphere entities. VCLib package mainly does the following:
  - Volume management on datastore (Create/Delete)
  - Volume management on Virtual Machines (Attach/Detach)
  - Storage Policy Management
- vSphere Cloud Provider changes to implement the cloud provider interfaces by calling into VCLib package.
- Modifications to e2e tests to accomodate the latest design changes.

@divyenpatel @rohitjogvmw @luomiao 

```release-note
vSphere cloud provider: vSphere cloud provider code refactoring
```