[AAF] Use global storage templates for PVC

OOM has now templates in order to create the needed PVC, using:

* a PV with a specific class when using a common nfs mount path between
nodes (sames as today use) --> is the default behavior today
* or a storage class if we want to use dynamic PV.
  On this case, we use (in order of priority):
  - persistence.storageClassOverride if set on the chart
  - global.persistence.storageClass if set globally
  - persistence.storageClass if set on the chart

I've also modified statefulset deployment so they can use their own PVC
instead of writing into a specific directory inside

I've also set to 'emptyDir' volumes when persistence is not enabled
(except for aaf-config-pvc and aaf-status-pvc, which means that AAF will
still not work when persistence is disabled).

Change-Id: I05f133f058ebd9678df9ac0b7ef32bb43689e94f
Issue-ID: OOM-1227
Signed-off-by: Sylvain Desbureaux <sylvain.desbureaux@orange.com>