GCP Filestore support with shared VPC

Epic Goal*

Support and document how to use the Filestore CSI driver  when OCP is running on a shared VPC on GCP .

 
Why is this important? (mandatory)

Shared VPC simplifies network management, allows consistent network policies, and provides a centralized view of network resources. It's important that the CSI drivers we ship support the OCP deployment models.

https://docs.openshift.com/container-platform/4.14/installing/installing_gcp/installing-gcp-user-infra-vpc.html#installing-gcp-user-infra-vpc

 
Scenarios (mandatory) 

Provide details for user scenarios including actions to be performed, platform specifications, and user personas.  

1. OCP is deployed on a service project and uses a shared VPC network instead of its own project network. Ensure filestore CSI works in this context.

 
Dependencies (internal and external) (mandatory)

Dependency on the Filestore CSI should be covered. The upstream driver doc mentions that shared VPC is supported with SC parameters

https://github.com/kubernetes-sigs/gcp-filestore-csi-driver/blob/master/README.md#supported-createvolume-parameters

Currently, admins need to create a SC manually so there should not be any operator work needed.

Contributing Teams(and contacts) (mandatory) 

Our expectation is that teams would modify the list below to fit the epic. Some epics may not need all the default groups but what is included here should accurately reflect who will be involved in delivering the epic.

• Development - STOR
• Documentation - STOR
• QE - STOR
• PX - 
• Others -

Acceptance Criteria (optional)

Ensure all drivers tests pass in a shared VPC context.

Done - Checklist (mandatory)

The following points apply to all epics and are what the OpenShift team believes are the minimum set of criteria that epics should meet for us to consider them potentially shippable. We request that epic owners modify this list to reflect the work to be completed in order to produce something that is potentially shippable.

• CI Testing -  Basic e2e automationTests are merged and completing successfully
• Documentation - Content development is complete.
• QE - Test scenarios are written and executed successfully.
• Technical Enablement - Slides are complete (if requested by PLM)
• Engineering Stories Merged
• All associated work items with the Epic are closed
• Epic status should be “Release Pending”