Pass source VS/PVC metadata to plugin by request parameters

[jeffyjf]

What type of PR is this?

/kind feature

What this PR does / why we need it:

When flag --extra-create-metadata set, inject the name and namespace of VolumeContentSource(VS or PVC) into CreateVolumeRequest parameters if user create PVC base on the VS/PVC.

Which issue(s) this PR fixes:

Fixes #1069

Special notes for your reviewer:

None

Does this PR introduce a user-facing change?:

Expose name and namespace of VolumeContentSource(VS/PVC) to plugin