1. Change listen addresses to URIs
2. Break out connectionSvc to support listeners and dialers based on schema
3. Add relay announcement and lookups part of discovery service
This will decrease the risk of running out of file descriptors for the
database and other bad things, which could otherwise potentially happen
if we're serving lots of requests and scanning in parallel, etc.
Windows doesn't have a per process open file limit like Unix so we don't
need to worry about it there.
