TS-938 - Don't merge

Adding the config and a gen_server to handle the c* nodes. But this uses elysium 0.1.7 so the files changed are really misleading.

Also the query seems to work, but it is not currently being used.
Cancel applies to interval timers as well, so you could use send_interval and only in the case of a manual call to update_nodes/0 you could cancel, call update_nodes/2 and then rerun the init function that sets up the initial interval timer. In any case, I think using send_after rather than apply_after is safer if you can't tolerate 2 processes concurrently updating the node list. Send_after means that this gen_server would receive a message and those are all serialized. You could use an FSM or an FSM flag to know whether a seed query is currently running and avoid running a second one as long as seed query was a linked process so that you get notification if it fails.

The choice is to code to allow 2 seed queries simultaneously, or to try to guarantee only one runs at any given time.