Rename entrypoints and make them less confusing

Currently searchlight-index is the endpoint for the initial indexing process, and agent_notification doesn't have one.

I propose renaming searchlight-index to either searchlight-manage (second choice searchlight-control), and adding an entrypoint for the notification listener 'searchlight-listener'. I'm happy to implement this if nobody has any objections, and i think this should be done prior to the devstack changes landing.