Adds the support for FlexGroup pool using the NFS storage mode.
The FlexGroup pool has a different view of aggregate capabilites,
changing them by a list of elements, instead of an element. They
are: `netapp_aggregate`, `netapp_raid_type`, `netapp_disk_type`
and `netapp_hybrid_aggregate`. The `netapp_aggregate_used_percent`
capability is an average of used percent of all FlexGroup's
aggregates.
The `utilization` capability is not calculated to FlexGroup pools,
it is always set to default value.
The driver cannot support consistency group with volumens that are
over FlexGroup pools.
ONTAP does not support FlexClone for file inside a FlexGroup pool,
so the operations of clone volume, create snapshot and create volume
from an image are implemented as the NFS generic driver.
The driver with FlexGroup pools has the snapshot support disabled, requiring
that setting the `nfs_snapshot_supprot` to true on the backend definition.
This config is the same as the NFS generic driver.
The driver image cache relies on FlexClone for file, so it is not applied
for volumes over FlexGroup pools. It can use the core cache image, though.
The QoS minimum is only enabled for FlexGroup pool if all nodes of the
FlexGroup support it.
Implements: blueprint netapp-flexgroup-support
Change-Id: I507083c3e34e5a5cf1db9a3d1f6bef47bd51a9f8
0cb7322ac6