Prune stale resourcepools,resources,dms and alarms

Prune stale resourcepools,resources,dms and alarms

Prune DB resource pools that don't exist in the authoritative source.

Steps for each prune cycle:

Retrieve current pool IDs from client for the specified ocloud
Get pool IDs from the database
For each pool ID that exists only in DB:
Remove all alarms associated with resources in that pool
Delete all resources belonging to that pool
Remove the resource pool itself

Test Plan:
PASS- Verify if the pruned respools,resources,alarms are not displayed
PASS- Resgression tests are passed

Change-Id: Idb4900e560d3b97a99d73d03ddd22cb295eb056c
Signed-off-by: vpachchi <vineela.pachchipulusu@windriver.com>