Add server-side GetResourceValues RPC method
Non-daemon aware clients (i.e. those that do not run as a daemon, or do not run a clientserver endpoint) may want to poll for the server's resource values. So, add a method for that. This is a bit complicated because now the dynslice_daemon will need to push its values into the DB... probably use node_attributes for this. But that is sort of an information leak; client A should not be able to see the server values for nodes currently held by client B. If A could see B's server-side node's values, plus its own server-side node values, it might be able to strategically maximize the chance that B's nodes would be stolen in preference to A's. Not sure about that...