Add foreignSource and foreignId parameters when sending events as an alternative to nodeId

Currently the forceRescan event requires the OpenNMS nodeid. We request that the forceRescan event be extended to support specifying the node to be rescanned by providing the foreignSource and foreignId of the node.

When external systems initiate activities that require a node rescan, these systems will in general not know the (internal) OpenNMS nodeid. In our case, our ERP (Netsuite) knows 'everything' about our equipment inventory and generates the foreignSource and foreignId.

Most OpenNMS REST APIs that require a nodeid also support FS:FID. We'd like to be able to initiate a forced rescan the same way.

Thanks,
John Black