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

## 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?

JIRA Issue: BA-108