Latency metrics are not location-aware

Currently, service latency metrics that are generated by the Poller are stored in RRDs in the /var/opennms/rrd/response/$ipAddr directories. Because the path does not include the Location, the resource path for overlapping IP addresses will be the same.

We need to change the resource path to include Location so that we can handle cases where overlapping IP address ranges are being managed by a distributed setup of OpenNMS + Minion.

This will probably involve writing an upgrade script to migrate existing metrics into a new location that includes the location, ie. /var/opennms/rrd/response/$location/$ipAddr.