Adding the zone, cluster, account level parameters
The parameters at scope (zone/cluster/pool/account) can be updated by updateConfiguration API with additional parameter zoneid/clusterid/accountid/storagepoolid
Whenever these scoped parameters are used in CS they get value from the corresponding details table if not defined get value from global parameter.
Same with the listConfiguration API with additional parameter zoneid/clusterid/accountid/storagepoolid
1) Added comments to VPC/VPCService/VPCManager interfaces
2) Moved VPC offering related methods from VpcService to the new interface - VpcProvisioningService
3) Fixed static nat creation in the VPC - used to result in NPE due to invalid method referencing while obtaining VPC VR information
The new policy is:
1. Generate a random IP.
2. Find the next available IP, start from the generated IP.
3. If we cannot find an available IP after certain times(10000 by default,
network.ipv6.search.retry.max) retry, give up.