VDisk list page

[ikopylov]

Linked issue: qoollo/bob#245

Page should contain the table of all vdisks with their availability in cluster. Example: 2/3 (if only 2 replicas are available).
Additionally, we need the ability to see the nodes on which the vdisk is located.

Info can be taken through REST API: https://github.com/qoollo/bob/blob/master/config-examples/openapi.yaml#L79