Add vfolder-data RBAC element type for vfolder data access control

== Motivation ==

Admins should be able to access vfolder listings and detail panels, but must not be able to access the data (files/directories) inside the vfolder. The current RBAC element type cannot separate vfolder metadata access from internal data access.

== Objective ==

Add a vfolder-data value to the RBAC element type, so that access to vfolder internal data can be managed separately from vfolder metadata access.

== Expected Sub Issues ==

1. Add vfolder-data to RBAC element type enum

2. Apply RBAC creator pattern for vfolder-data

3. Data migration for vfolder-data RBAC element type

JIRA Issue: BA-5377