since we can now backup multiple datastores in the same media-set,
we show the datastores as first level below that
the final tree structucture looks like this:
tapepool A
- media set 1
- datastore I
- tape x
- ct/100
- ct/100/2020-01-01T00:00:00Z
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>