Add resource group property to list accessible vfolder hosts (storage volumes)

[achimnol]

Motivation

In some setups, resource groups reside in distributed clusters on multiple distant regions and they may have limited access to cluster-local storage only.

In such cases, if a user or project is allowed access multiple resource groups and multiple storage volumes, creating a dot-prefixed automount vfolder in a specific storage makes the user unable to spawn compute sessions on other resource groups.

Proposed fix

Let's add an explicit resource group property to track which storage volumes (aka vfolder hosts) can be accessed, and filter/validate the availability of them when mounting vfolders in the sessions.

We also need to update all vfolder selection UI (WebUI and FastTrack) to have a resource-group based filtering.

Design issues

• Should we allow users to create the vfolders with the same name but in different storage volumes?
  • e.g., automount vfolders for each resource group
  • If so, how could we minimize the user's confusion?
  • If not, should we prohibit session creation with vfolders on different resource groups? How do we warn the users?
  • Or, should we silently skip mounting automount vfolders, while reporting explicit failure for non-automount vfolders?